Precision BioSciences (DTIL) 10-Q 12 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 06, 2019
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2019
Entity Registrant Name	PRECISION BIOSCIENCES INC
Entity Central Index Key	0001357874
Trading Symbol	DTIL
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Common Stock, Shares Outstanding		50,787,317
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Ex Transition Period	false
Entity File Number	001-38841
Entity Tax Identification Number	20-4206017
Entity Address, Address Line One	302 East Pettigrew St.
Entity Address, Address Line Two	Suite A-100
Entity Address, City or Town	Durham
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27701
City Area Code	919
Local Phone Number	314-5512
Title of 12(b) Security	Common Stock, par value $0.000005 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 206,265	$ 103,193
Accounts receivable	250	523
Prepaid expenses	10,738	8,913
Other current assets	2,248	3,046
Total current assets	219,501	115,675
Property, equipment, and software—net	38,959	21,147
Intangible assets—net	1,446	1,466
Other assets	392	312
Total assets	260,298	138,600
Current liabilities:
Accounts payable	4,465	2,218
Accrued compensation	2,961	965
Accrued clinical and research and development expenses	3,556	1,569
Accrued other expenses and other current liabilities	1,977	887
Deferred revenue	10,767	8,436
Total current liabilities	23,726	14,075
Deferred revenue—noncurrent	77,887	82,807
Deferred rent—noncurrent	2,897	1,758
Total liabilities	104,510	98,640
Commitments and contingencies (Note 4)
Stockholders’ equity:
Preferred stock
Additional paid-in capital	312,891	126,094
Accumulated deficit	(156,151)	(85,187)
Treasury stock	(952)	(952)
Total stockholders’ equity	155,788	39,960
Total liabilities and stockholders’ equity	$ 260,298	138,600
Series A Convertible Preferred Stock
Stockholders’ equity:
Preferred stock		3
Total stockholders’ equity		3
Series B Convertible Preferred Stock
Stockholders’ equity:
Preferred stock		2
Total stockholders’ equity		$ 2

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	0
Preferred stock, shares issued	0
Preferred stock, shares outstanding	0
Common stock, par value	$ 0.000005	$ 0.000005
Common stock, shares authorized	200,000,000	130,000,000
Common stock, shares issued	51,470,176	16,717,117
Common stock, shares outstanding	50,659,704	15,906,645
Series A Convertible Preferred Stock
Preferred stock, par value		$ 0.0001
Preferred stock, shares authorized		25,650,000
Preferred stock, shares issued		25,650,000
Preferred stock, shares outstanding		25,650,000
Series B Convertible Preferred Stock
Preferred stock, par value		$ 0.0001
Preferred stock, shares authorized		21,956,100
Preferred stock, shares issued		21,956,095
Preferred stock, shares outstanding		21,956,095

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 4,865	$ 2,541	$ 15,716	$ 5,943
Operating expenses
Research and development	19,791	9,737	62,512	28,723
General and administrative	7,052	3,251	18,547	9,027
Total operating expenses	26,843	12,988	81,059	37,750
Loss from operations	(21,978)	(10,447)	(65,343)	(31,807)
Other income (expense), net:
Change in fair value of convertible note payable			(9,758)
Interest expense			(182)
Interest income	1,236	691	3,322	1,213
Total other income (expense), net	1,236	691	(6,618)	1,213
Net loss and net loss attributable to common stockholders	$ (20,742)	$ (9,756)	$ (71,961)	$ (30,594)
Net loss per share attributable to common stockholders- basic and diluted	$ (0.41)	$ (0.62)	$ (1.85)	$ (1.94)
Weighted average shares of common stock outstanding- basic and diluted	50,623,665	15,816,748	39,002,304	15,751,091

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Treasury Stock
Beginning balance at Dec. 31, 2017	$ (26,369)	$ 3			$ 13,691	$ (39,111)	$ (952)
Beginning balance, Shares at Dec. 31, 2017		25,650,000		16,496,801
Stock option exercises	20				20
Stock option exercises, Shares				29,802
Share-based compensation expense	151				189	(38)
Net loss	(9,012)					(9,012)
Ending balance at Mar. 31, 2018	(35,210)	$ 3			13,900	(48,161)	(952)
Ending balance, Shares at Mar. 31, 2018		25,650,000		16,526,603
Beginning balance at Dec. 31, 2017	(26,369)	$ 3			13,691	(39,111)	(952)
Beginning balance, Shares at Dec. 31, 2017		25,650,000		16,496,801
Net loss	(30,594)
Ending balance at Sep. 30, 2018	53,586	$ 3	$ 2		124,276	(69,743)	(952)
Ending balance, Shares at Sep. 30, 2018		25,650,000	21,956,095	16,636,815
Beginning balance at Mar. 31, 2018	(35,210)	$ 3			13,900	(48,161)	(952)
Beginning balance, Shares at Mar. 31, 2018		25,650,000		16,526,603
Issuance of Series B convertible preferred stock, net of issuance costs	87,826		$ 2		87,824
Issuance of Series B convertible preferred stock, net of issuance costs, shares			17,579,843
Stock option exercises	62				62
Stock option exercises, Shares				65,449
Share-based compensation expense	254				254
Net loss	(11,826)					(11,826)
Ending balance at Jun. 30, 2018	41,106	$ 3	$ 2		102,040	(59,987)	(952)
Ending balance, Shares at Jun. 30, 2018		25,650,000	17,579,843	16,592,052
Issuance of Series B convertible preferred stock, net of issuance costs	21,917				21,917
Issuance of Series B convertible preferred stock, net of issuance costs, shares			4,376,252
Stock option exercises	27				27
Stock option exercises, Shares				44,763
Share-based compensation expense	292				292
Net loss	(9,756)					(9,756)
Ending balance at Sep. 30, 2018	53,586	$ 3	$ 2		124,276	(69,743)	(952)
Ending balance, Shares at Sep. 30, 2018		25,650,000	21,956,095	16,636,815
Beginning balance at Dec. 31, 2018	39,960	$ 3	$ 2		126,094	(85,187)	(952)
Beginning balance, Shares at Dec. 31, 2018		25,650,000	21,956,095	16,717,117
Adjustment to beginning accumulated deficit from adoption of ASU 2014-09 at Dec. 31, 2018	997					997
Stock option exercises	107				107
Stock option exercises, Shares				145,975
Share-based compensation expense	1,549				1,549
Net loss	(31,783)					(31,783)
Ending balance at Mar. 31, 2019	10,830	$ 3	$ 2		127,750	(115,973)	(952)
Ending balance, Shares at Mar. 31, 2019		25,650,000	21,956,095	16,863,092
Beginning balance at Dec. 31, 2018	39,960	$ 3	$ 2		126,094	(85,187)	(952)
Beginning balance, Shares at Dec. 31, 2018		25,650,000	21,956,095	16,717,117
Adjustment to beginning accumulated deficit from adoption of ASU 2014-09 at Dec. 31, 2018	$ 997					997
Stock option exercises, Shares	445,408
Net loss	$ (71,961)
Ending balance at Sep. 30, 2019	155,788				312,891	(156,151)	(952)
Ending balance, Shares at Sep. 30, 2019				51,470,176
Beginning balance at Mar. 31, 2019	10,830	$ 3	$ 2		127,750	(115,973)	(952)
Beginning balance, Shares at Mar. 31, 2019		25,650,000	21,956,095	16,863,092
Conversion of convertible preferred stock into common stock upon initial public offering		$ (3)	$ (2)		5
Conversion of convertible preferred stock into common stock upon initial public offering, shares		(25,650,000)	(21,956,095)	22,301,190
Issuance of common stock upon conversion of convertible notes	49,490				49,490
Issuance of common stock upon conversion of convertible notes, shares				2,921,461
Issuance of common stock in initial public offering, net of discounts and issuance costs	130,543				130,543
Issuance of common stock in initial public offering, net of discounts and issuance costs, shares				9,085,000
Stock option exercises	272				272
Stock option exercises, Shares				230,272
Share-based compensation expense	2,279				2,279
Net loss	(19,436)					(19,436)
Ending balance at Jun. 30, 2019	173,978				310,339	(135,409)	(952)
Ending balance, Shares at Jun. 30, 2019				51,401,015
Stock option exercises	61				61
Stock option exercises, Shares				69,161
Share-based compensation expense	2,491				2,491
Net loss	(20,742)					(20,742)
Ending balance at Sep. 30, 2019	$ 155,788				$ 312,891	$ (156,151)	$ (952)
Ending balance, Shares at Sep. 30, 2019				51,470,176

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (71,961)	$ (30,594)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,508	1,555
Share-based compensation	6,319	697
Loss on disposal of assets	22	8
Non-cash interest expense	182
Change in fair value of convertible notes payable	9,758
Changes in operating assets and liabilities:
Prepaid expenses	(1,826)	(8,634)
Accounts receivable	273	(6,523)
Other assets and other current assets	(601)	(349)
Accounts payable	597	953
Accrued other expenses and other current liabilities	4,862	2,780
Deferred revenue	(1,592)	1,296
Net cash used in operating activities	(50,459)	(38,811)
Cash flows from investing activities:
Acquisition of license rights		(1,400)
Purchases of property, equipment and software	(19,137)	(4,407)
Proceeds from disposal of assets		15
Net cash used in investing activities	(19,137)	(5,792)
Cash flows from financing activities:
Proceeds from stock option exercises	440	109
Issuance of Series B convertible preferred stock, net of issuance costs		109,741
Deferred offering costs	(2,507)	(481)
Issuance of convertible notes	39,550
Proceeds from IPO, net of underwriting discounts and commissions	135,185
Net cash provided by financing activities	172,668	109,369
Net increase in cash and cash equivalents	103,072	64,766
Cash and cash equivalents—beginning of period	103,193	62,802
Cash and cash equivalents —end of period	206,265	127,568
Supplemental disclosures of noncash financing and investing activities:
Common stock issued on conversion of convertible notes	49,490
Property, equipment and software additions included in accounts payable, accrued expenses and other current liabilities	$ 3,524	2,187
Deferred offering costs included in accounts payable, accrued expenses and other current liabilities		$ 857

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	NOTE 1: DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Description of Business Precision BioSciences, Inc. (the “Company”) was incorporated on January 26, 2006 under the laws of the State of Delaware and is based in Durham, North Carolina. The Company is focused on utilizing its proprietary genome editing platform to help overcome cancers, cure genetic diseases and enable the development of safer, more productive food sources. The Company’s 100% owned subsidiary, Precision PlantSciences, Inc., was incorporated on January 4, 2012. Precision PlantSciences, Inc. amended its certificate of incorporation on January 16, 2018 to change its name to Elo Life Systems, Inc. Elo Life Systems Australia Pty Ltd was incorporated on May 29, 2018 as a 100% owned subsidiary of Elo Life Systems, Inc. Additionally, the Company’s 100% owned subsidiary Precision BioSciences UK Limited was incorporated on June 17, 2019. The accompanying condensed consolidated financial statements include the accounts of the Company and its subsidiaries. Intercompany balances and transactions have been eliminated in consolidation. Since its inception, the Company has devoted substantially all of its efforts to research and development activities, recruiting skilled personnel, developing manufacturing processes, establishing its intellectual property portfolio and providing general and administrative support for these operations. The Company is subject to a number of risks similar to those of other companies conducting high-risk, early-stage research and development of product candidates. Principal among these risks are dependence on key individuals and intellectual property, competition from other products and companies, and the technical risks associated with the successful research, development and clinical manufacturing of its product candidates. The Company’s success is dependent upon its ability to continue to raise additional capital in order to fund ongoing research and development, obtain regulatory approval of its products, successfully commercialize its products, generate revenue, meet its obligations, and, ultimately, attain profitable operations. On April 1, 2019, the Company completed its initial public offering (“IPO”) in which the Company issued and sold 9,085,000 shares In connection with the IPO, on March 15, 2019 the Company effected a reverse split of shares of the Company’s common stock on a 1-for-2.134686 basis (the “Reverse Stock Split”) of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for the Company’s Series A and Series B preferred stock. Accordingly, all common shares, stock option shares, and per share amounts for all periods presented in the accompanying financial statements and notes thereto have been retroactively adjusted, where applicable, to reflect this Reverse Stock Split and adjustment of the preferred stock conversion ratios. Authorized common shares were not affected by the Reverse Stock Split. Upon the closing of the IPO, all of the outstanding shares of convertible preferred stock automatically converted into 22,301,190 shares of common stock at the applicable ratio then in effect and the outstanding convertible promissory notes including accrued interest were settled into 2,921,461 shares of common stock (see Note 5). Subsequent to the closing of the IPO, there were no shares of Series A or Series B convertible preferred stock or convertible promissory notes outstanding. Management believes that existing cash and cash equivalents will allow the Company to continue its operations into 2021. In the absence of a significant source of recurring revenue, the continued viability of the Company beyond that point is dependent on its ability to continue to raise additional capital to finance its operations. There can be no assurance that the Company will be able to obtain sufficient capital to cover its costs on acceptable terms, if at all. Reclassifications Certain reclassifications have been made to the presentation of amounts in our Condensed Consolidated Balance Sheet as of September 30, 2019 to conform to the prior year presentation. Specifically, certain current liabilities were reclassified from accrued expenses and other current liabilities and are now presented separately on our Condensed Consolidated Balance Sheets. Unaudited Interim Financial Information The accompanying unaudited condensed consolidated financial statements and notes have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in the annual financial statements, prepared in accordance with accounting principles generally accepted in the U.S., have been condensed or omitted pursuant to those rules and regulations. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2018 included in the Company's final prospectus that forms a part of the Company’s Registration Statement on Form S-1 (Reg. No. 333-230034), filed with the SEC pursuant to Rule 424(b)(4) on March 28, 2019. The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s consolidated financial position as of September 30, 2019 and consolidated results of operations for the three and nine months ended September 30, 2019 and 2018 and the consolidated cash flows for the nine months ended September 30, 2019 and 2018, have been made. The Company’s consolidated results of operations for the three and nine months ended September 30, 2019 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2019. Summary of Significant Accounting Policies Revenue Recognition for Contracts with Customers The Company’s revenues are generated primarily through collaborative research, license, development and commercialization agreements. Effective January 1, 2019, the Company adopted Accounting Standards Update (“ASU”) No. 2014-09, Revenue: Revenue from Contracts with Customers Revenue Recognition At contract inception, once the contract is determined to be within the scope of ASC 606, the Company evaluates the performance obligations promised in the contract that are based on goods and services that will be transferred to the customer and determines whether those obligations are both (i) capable of being distinct and (ii) distinct in the context of the contract. Goods or services that meet these criteria are considered distinct performance obligations. If both these criteria are not met, the goods and services are combined into a single performance obligation. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, these options are considered performance obligations. The exercise of a material right is accounted for as a contract modification for accounting purposes. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue within current liabilities in the accompanying condensed consolidated balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue – noncurrent. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets in the Other current assets line item in the condensed consolidated balance sheets. Milestone Payments – If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. Royalties – For arrangements that include sales-based royalties, including milestone payments based on a level of sales, which are the result of a customer-vendor relationship and for which the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied or partially satisfied. To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. Significant Financing Component – In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed each of its revenue arrangements in order to determine whether a significant financing component exists and concluded that a significant financing component does not exist in any of its arrangements. Collaborative Arrangements – The Company has entered into collaboration agreements, which are within the scope of ASC 606, to discover, develop, manufacture and commercialize product candidates. The terms of these agreements typically contain multiple promises or obligations, which may include: (1) licenses, or options to obtain licenses, to use the Company’s technology, (2) research and development activities to be performed on behalf of the collaboration partner, and (3) in certain cases, services in connection with the manufacturing of preclinical and clinical material. Payments the Company receives under these arrangements typically include one or more of the following: non-refundable, upfront license fees; option exercise fees; funding of research and/or development efforts; clinical and development, regulatory, and sales milestone payments; and royalties on future product sales. The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808, Collaborative Arrangements For a complete discussion of accounting for collaboration revenues, see Note 8, “Collaboration and license agreements.” Recent Accounting Pronouncements As a result of adopting ASC 606, the Company recorded a $1.0 million transition adjustment to reduce the opening balance of accumulated deficit in the first quarter of 2019 primarily as a result of the treatment of the up-front consideration received from the Company’s collaboration agreements under superseded prior revenue recognition guidance. A summary of the amount by which each financial statement line item was affected by the impact of the cumulative adjustment is set forth in the table below: Impact of ASC 606 Adoption on Condensed Consolidated Balance Sheet as of January 1, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Deferred revenue - current liabilities $ 8,029 $ 407 $ 8,436 Deferred revenue - noncurrent liabilities 82,217 590 82,807 Accumulated deficit (84,190 ) (997 ) (85,187 ) A summary of the amount by which each financial statement line item was affected in the current reporting period by ASC 606 as compared with the guidance that was in effect prior to adoption is set forth in the tables below: Impact of ASC 606 Adoption on Condensed Consolidated Balance Sheet as of September 30, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Deferred revenue - current liabilities 10,767 1,433 12,200 Deferred revenue - noncurrent liabilities 77,887 888 78,775 Accumulated deficit (156,151 ) 2,321 (153,830 ) Impact of ASC 606 Adoption on Condensed Consolidated Statement of Operations for the Three Months Ended September 30, 2019 Impact of ASC 606 Adoption on Condensed Consolidated Statement of Operations for the Nine Months Ended September 30, 2019 (in thousands, except per share data) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Revenue $ 4,865 $ (218 ) $ 4,647 $ 15,716 $ (1,324 ) $ 14,392 Net loss (20,742 ) (218 ) (20,960 ) (71,961 ) (1,324 ) (73,285 ) Net loss per share - basic and diluted (0.41 ) (0.00 ) (0.41 ) (1.85 ) (0.03 ) (1.88 ) Impact of ASC 606 Adoption on Condensed Consolidated Statement of Cash Flows for the Nine Months Ended September 30, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Net loss $ (71,961 ) $ (1,324 ) $ (73,285 ) Changes in deferred revenue (1,592 ) 1,324 (268 ) During the nine months ended September 30, 2019, the Company recorded $6.4 million in revenue that was included in deferred revenue as of December 31, 2018. The most significant change to the Company’s revenue recognition as a result of the adoption of ASC 606 relates to the accounting for certain option fees and milestone payments in determining the transaction price (step (iii)), and the revenue recognition pattern (step (v)) related to the Company’s development and commercial license agreement with Laboratoires Servier (“Servier”) (see Note 8). Under ASC 605, the option fees payable by the Company to exercise the 50/50 co-development and co-promotion option was accounted for as a reduction in the arrangement consideration, and certain development milestones that may be earned for early-stage pre-IND development milestones were included in the arrangement consideration as the early-stage pre-IND development milestones were deemed to be non-substantive. Under ASC 606, the option fees were not accounted for as a reduction in the transaction price as the option fees are contingent upon Servier’s exercise of its commercial (customer) options on licensed product candidates, and the milestone payments were excluded from the transaction price based on the assessment of the most likely amount and application of the variable consideration constraint, since the milestones relate to successful achievement of certain developmental goals, which might not be achieved. In addition, under ASC 605, the Company recognized revenue on a straight‑line basis over the period the Company expected to complete its obligations. Under ASC 606, the Company recognizes revenue based on the proportional performance of the services related to the performance obligation expected. For further discussion of the adoption of ASC 606 see Note 8, “Collaboration and license agreements.” Collaborative Arrangements (Topic 808)—Clarifying the Interaction between Topic 808 and ASC 606 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) Leases, Targeted Improvements to ASC 842, Leases , Leases The Company is currently evaluating the potential impact ASU 2016-02 may have on its financial position, results of operations, and related footnotes. The Company expects it will elect to utilize the available package of practical expedients permitted under the transition guidance within the new standard, which does not require the reassessment of the following: i) whether existing or expired arrangements are or contain a lease, ii) the lease classification of existing or expired leases, and iii) whether previous initial direct costs would qualify for capitalization under the new lease standard.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Stockholders Equity Note [Abstract]
Stockholders' Equity	NOTE 2 : STOCKHOLDERS’ EQUITY Capital Structure Upon the closing of the IPO, all of the Company’s outstanding shares of the Series A and Series B convertible preferred stock automatically converted into 22,301,190 shares of common stock and the Company’s outstanding convertible promissory notes including accrued interest converted into 2,921,461 shares of common stock at the applicable conversion ratio. Subsequent to the closing of the IPO, there were no shares of preferred stock outstanding. On April 1, 2019, the Company filed an amendment to its amended and restated certificate of incorporation pursuant to which, among other things, the Company increased its authorized shares to 210,000,000 shares of capital stock, of which 200,000,000 shares were designated as $0.000005 par value common stock and 10,000,000 shares were designated as $0.0001 par value preferred stock.

Stock Options

Stock Options	9 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
STOCK OPTIONS	NOTE 3 : STOCK OPTIONS Under the terms of its stock option plans, the Company’s board of directors may grant stock options to employees, directors and service providers. The Company granted stock options under the 2006 Stock Incentive Plan (“2006 Plan”) until April 2015 when the 2015 Stock Incentive Plan (“2015 Plan”) was adopted. The 2006 Plan expired in 2016 and there are no remaining shares available to be granted under the 2006 Plan. There were 1,397,203 stock options outstanding under the 2006 Plan as of September 30, 2019. Upon adoption of the 2015 Plan, there were 5,270,095 shares of common stock reserved for issuance. In May 2018, the Company amended the 2015 Plan to increase the number of shares reserved for issuance to 8,211,980. The 2015 Plan had 6,111,373 stock options outstanding as of September 30, 2019. The Company’s board of directors determines the terms of stock options granted under the 2015 Plan, including option exercise prices and vesting. On March 12, 2019, the Company’s board of directors adopted, and the Company’s stockholders approved the Precision BioSciences, Inc. 2019 Incentive Award Plan (“2019 Plan”) and the 2019 Employee Stock Purchase Plan (“2019 ESPP”), both of which became effective on March 27, 2019. On March 27, 2019, the Company ceased granting new awards under the 2015 Plan. The 2019 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock, restricted stock units and other share-based awards initially equal to 4,750,000 shares of common stock. The 2019 Plan includes an annual increase of common stock shares on the first day of each calendar year beginning January 1, 2020 and ending on January 1, 2029 by an amount equal to the lesser of (i) 4% of the aggregate number of shares of common stock outstanding on the final day of the immediately preceding calendar year and (ii) such smaller number of shares of common stock as determined by the board of directors (but no more than 5,000,000 shares may be issued upon the exercise of incentive stock options), plus any shares that are subject to awards outstanding under the Company’s 2006 Plan and 2015 Plan as of the effective date of the 2019 Plan that expire, lapse, or are terminated, exchanged for cash, surrendered, repurchased, or canceled without having been fully exercised or forfeited, to the extent so unused. The 2019 Plan had 1,539,054 stock options outstanding as of September 30, 2019. The 2019 ESPP provides for the option to purchase initially up to 525,000 shares of the Company’s common stock plus an annual increase on the first day of each calendar year beginning January 1, 2020 and ending on and including January 1, 2029 by an amount equal to the lesser of (i) 1% of the shares outstanding on the final day of the immediately preceding calendar year and (ii) such smaller number of shares as is determined by our board of directors, provided that no more than 5,250,000 shares of our common stock may be issued under our 2019 ESPP. The purchase price of the shares, in the absence of a contrary designation, will be 85% of the lower of the fair market value of our common stock on the first trading day of the offering period or on the purchase date. The first ESPP offering period commenced on October 21, 2019 and will end on February 29, 2020. The Company recorded employee and nonemployee share-based compensation expense as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Employee $ 2,328 $ 292 $ 5,905 $ 690 Nonemployee 163 - 414 7 $ 2,491 $ 292 $ 6,319 $ 697 Share-based compensation expense related to stock options is included in the following line items in the condensed Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Research and development $ 1,615 $ 224 $ 4,131 $ 502 General and administrative 876 68 2,188 195 $ 2,491 $ 292 $ 6,319 $ 697 Determining the appropriate fair value model to measure the fair value of the stock option grants on the date of grant and the related assumptions requires judgment. The Company granted 2,115,331 stock options for the nine months ended September 30, 2019. The fair value of each stock option grant is estimated using a Black-Scholes option-pricing model on the date of grant as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2019 Estimated dividend yield 0.00 % 0.00 % Weighted-average expected stock price volatility 68.13 % 68.16 % Weighted-average risk-free interest rate 1.74 % 2.08 % Expected life of options (in years) 6.81 6.60 Weighted-average fair value per option $ 7.57 $ 8.20 The expected volatility rates are estimated based on the actual volatility of comparable public companies over the expected term. The expected life represents the average time that stock options that vest are expected to be outstanding. The Company does not have sufficient history of exercising stock options to estimate the expected term of employee stock options and thus continues to calculate expected life based on the midpoint between the vesting date and the contractual term which is in accordance with the simplified method. The expected term for share-based compensation granted to nonemployees is the contractual life. The risk-free rate is based on the United States Treasury yield curve during the expected life of the option. The following table summarizes activity in the Company’s stock option plans for the nine months ended September 30, 2019: Outstanding Option Shares Weighted- Average Exercise Price Balance as of January 1, 2019 7,763,464 $ 5.00 Granted 2,115,331 12.48 Exercised (445,408 ) 0.99 Forfeited/canceled (385,757 ) 10.46 Balance as of September 30, 2019 9,047,630 6.72 The intrinsic value of stock options exercised was $5.3 million and $1.0 million during the nine months ended September 30, 2019 and 2018, respectively. There was approximately $30.3 million of total unrecognized compensation cost related to unvested stock options as of September 30, 2019, which is expected

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	NOTE 4 : COMMITMENTS AND CONTINGENCIES Litigation The Company is not subject to any material legal proceedings. Leases The Company leases office and laboratory space under long-term operating leases. All the leases provide tenant improvement allowances and rent abatements as incentives for the Company to either enter into the initial lease agreement or expand within an existing premises already under lease. The Company leases office and laboratory space at 302 East Pettigrew Street, Durham, North Carolina, which is the Company’s corporate headquarters. The property is leased through July 2024 with the option to extend. The Company leases laboratory and office space at 5 Laboratory Drive, Research Triangle Park, North Carolina. The property is leased through April 2026 with the option to extend. The Company leases laboratory space at 20 TW Alexander Drive, Research Triangle Park, North Carolina. The property is leased through August 2026 with the option to extend. The following is a schedule of future minimum lease payments for all leases as of September 30, 2019 (in thousands): Operating Leases Remainder of 2019 $ 659 2020 2,690 2021 2,635 2022 2,718 2023 2,795 2024 and beyond 3,742 Supply Agreements The Company enters into contracts in the normal course of business with contract manufacturing organizations (“CMOs”) for the manufacture of clinical trial materials and contract research organizations (“CROs”) for clinical trial services. These agreements provide for termination at the request of either party with less than one-year notice and are, therefore, cancelable contracts and, if canceled, are not anticipated to have a material effect on the condensed

Debt

Debt	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Debt	NOTE 5 : DEBT In March 2019, the Company entered into a note purchase agreement pursuant to which it sold and issued an aggregate of $39.6 million of convertible promissory notes (the “2019 Notes”). The 2019 Notes accrued interest at a rate of 6% per annum. The 2019 Notes were settled in 2,921,461 shares of common stock in connection with the closing of the Company’s IPO (see Note 1) at a settlement price of $13.60 per share (equal to 85% of the IPO price per share). On issuance, the Company elected to account for the 2019 Notes at fair value with any changes in fair value being recognized through the condensed consolidated statements of operations until the 2019 Notes are settled. The fair value of the 2019 Notes was determined to be $39.6 million on issuance and $49.4 million as of April 1, 2019, the settlement date. For the nine months ended September 30, 2019, the Company recognized $9.8 million of expense as changes in fair value and $0.2 million of interest expense. Revolving Line In May 2019, the Company entered into a loan and security agreement with Pacific Western Bank (the “Pacific Western Loan Agreement”) pursuant to which the Company may request advances on a revolving line of credit of up to an aggregate principal of $50.0 million (the “Revolving Line”). The maturity date of the Revolving Line is May 15, 2022. The Revolving Line bears interest at an annual rate equal to the greater of (i) 1.25% below the prime rate then in effect, or (ii) 4.25% at all times when the Company maintains a daily balance of cash in its demand deposit accounts at Pacific Western Bank of at least $25.0 million, and the greater of (i) 0.25% above the prime rate then in effect; or (ii) 5.75% at all times when the Company does not maintain a daily balance of cash in demand deposit accounts at Pacific Western Bank of at least $25.0 million. The Pacific Western Loan Agreement requires that the Company pay a quarterly fee in an amount equal to 0.50% per annum of the unused portion of the Revolving Line. The unused fee shall be waived for any quarter the Company maintains a daily balance in its demand deposit accounts of at least $25.0 million. The Pacific Western Loan Agreement includes customary representations, warranties and covenants (affirmative and negative). There were no borrowings, and the Company was in compliance with its financial covenants, under the Pacific Western Loan Agreement as of September 30, 2019.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	NOTE 6 : Income Taxes The Company estimates an annual effective tax rate of 0% for the year ending December 31, 2019 as the Company incurred losses for the nine months ended September 30, 2019 and is forecasting additional losses through the remainder of fiscal year ending December 31, 2019, resulting in an estimated net loss for both financial statement and tax purposes for the year ended December 31, 2019. Therefore, no federal or state income taxes are expected and none have been recorded at this time. Income taxes have been accounted for using the liability method in accordance with FASB ASC 740. Due to the Company's history of losses since inception, there is not enough evidence at this time to support that the Company will generate future income of a sufficient amount and nature to utilize the benefits of its net deferred tax assets. Accordingly, the deferred tax assets have been reduced by a full valuation allowance, since the Company does not currently believe that realization of its deferred tax assets is more likely than not. As of September 30, 2019, the Company had no unrecognized income tax benefits that would reduce the Company’s effective tax rate if recognized.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
FAIR VALUE MEASUREMENTS	NOTE 7 : FAIR VALUE MEASUREMENTS The carrying amounts of the Company’s financial instruments, including accounts receivable, accounts payable, and accrued expenses and other current liabilities, approximate their respective fair values due to their short-term nature. The Company uses a three-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis and to minimize the use of unobservable inputs when determining their fair value. The three tiers are defined as follows: Level 1—Observable inputs based on unadjusted quoted prices in active markets for identical assets or liabilities Level 2—Inputs, other than quoted prices in active markets, that are observable either directly or indirectly Level 3—Unobservable inputs for which there is little or no market date, which require the Company to develop its own assumptions The Company classifies investments in money market funds within Level 1 as the prices are available from quoted prices in active markets. Investments in repurchase agreements are classified within Level 2 as these instruments are valued using observable market inputs including reported trades, broker/dealer quotes, bids and/or offers. As of September 30, 2019 and December 31, 2018, the Company held cash equivalents which are composed of money market funds and repurchase agreements that were purchased through repurchase intermediary banks and collateralized by deposits in the form of government securities and obligations. The following represents assets measured at fair value on a recurring basis by the Company (in thousands): September 30, 2019 Fair Value Level 1 Level 2 Level 3 Assets: Money market funds $ 1,227 $ 1,227 $ — $ — Repurchase agreements 201,000 — 201,000 — $ 202,227 $ 1,227 $ 201,000 $ — December 31, 2018 Fair Value Level 1 Level 2 Level 3 Assets: Money market funds $ 781 $ 781 $ — $ — Repurchase agreements 94,500 — 94,500 — $ 95,281 $ 781 $ 94,500 $ —

Collaboration and License Agree

Collaboration and License Agreements	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
COLLABORATION AND LICENSE AGREEMENTS	NOTE 8 : COLLABORATION AND LICENSE AGREEMENTS Development and Commercial License Agreement with Servier On February 24, 2016, the Company entered into a development and commercial license agreement, as subsequently amended, with Baxalta (now Shire), which was assigned to Servier in connection with its acquisition of Shire’s oncology business in August 2018. This agreement establishes a collaboration between the Company and Servier to develop allogeneic chimeric antigen receptor T (“CAR T”) cell therapies for up to six unique antigen targets selected by Servier. Servier selected one target at the agreement’s inception, and Servier is entitled to select the remaining five targets over the first four years of the agreement. Servier is required to make a milestone payment to the Company upon achievement of an early-stage pre- investigational new drug application (“IND”) development milestone event completed for each of the remaining five targets selected, if any. The Company granted Servier a development license and will perform early-stage R&D on the selected targets and develop the resulting therapeutic product candidates through Phase 1 clinical trials and manufacture clinical trial material for use in Phase 2 clinical trials. Also, the Company and Servier have formed a joint steering committee (“JSC”) to provide high-level oversight and decision making regarding the activities covered under the agreement. The Company received an upfront payment of $105.0 million under the agreement. At the Phase 2 readiness stage for any product candidate, Servier may exercise a commercial option, subject to payment of commercial option exercise fees, to proceed with development and commercialization of the product candidate and perform late-stage R&D, including Phase 2 and Phase 3 clinical trials and obtaining regulatory approvals. The Company has the ability to receive total payments, in the aggregate across all six targets that may be selected by Servier, of up to approximately $1.6 billion, including the upfront payment of $105.0 million and up to $1.5 billion in milestone payments, consisting of up to $401.3 million in development milestone payments and up to $1.1 billion in commercial milestone payments. The Company is also entitled to receive tiered royalties ranging from the mid-single digit percentages to the sub-teen percentages on worldwide net sales of any products developed, subject to customary potential reductions. The Company also has the right to opt in and participate in the development and commercialization of any products resulting from the collaboration through a 50/50 codevelopment and co-promotion option in the United States. This will require the Company to pay a codevelopment and co-promotion option fee on each licensed product for which the Company elects to participate. This option is exercisable at the Phase 2 readiness stage and only after Servier exercises its commercial option. The Company assessed this arrangement in accordance with ASC 606 and concluded that the promises in the agreement represent transactions with a customer. The Company has determined that the promises associated with the research and development activities for each of the six targets are not distinct because they are all based on the ARCUS proprietary genome editing platform. The Company has concluded that the agreement with Servier contains the following promises: (i) a development license; (ii) performance of early-stage R&D services, (iii) the manufacture of clinical trial material for use in Phase 2 clinical trials, and (iv) JSC participation. The Company determined that the license, manufacture of clinical trial material, and R&D services were not distinct from each other, as the license, pre-clinical and clinical supply, and R&D services are highly interdependent upon one another. Participation on the JSC to oversee the research and development activities are combined into the single performance obligation as these activities are highly interdependent with the other R&D services. As such, the Company determined that these promises should be combined into a single performance obligation. Under the agreement with Servier, in order to evaluate the appropriate transaction price, the Company determined that the upfront amount of $105.0 million constituted the entire consideration to be included in the transaction price as of the outset of the arrangement. As such, this amount was allocated to the single performance obligation. The commercial option exercise fees that may be received are excluded from the transaction price until each customer option is exercised as it was determined that the options are not material rights. The potential development milestone payments that the Company is eligible to receive prior to the exercise of the options as well as commercial milestones, were excluded from the transaction price, as all milestone amounts were fully constrained based on the probability of achievement, since the milestones relate to successful achievement of certain developmental goals, which might not be achieved. None of the future royalty payments were included in the transaction price, as the potential payments represent sales-based consideration. The Company will reevaluate the transaction price, including all constrained amounts, at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur, and, if necessary, adjust its estimate of the transaction price. The Company recognizes revenue from the upfront payment of $105.0 million based on an input method in the form of research effort relative to expected research effort at the completion of the performance obligation, which is based on the relative costs and timelines of the related to the R&D activities incurred and expected to be incurred in the future to satisfy the performance obligation. This period is estimated to be approximately 7 years. The transfer of control occurs over this time period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. The estimated period of performance and project cost is reviewed quarterly and adjusted, as needed, to reflect the Company’s current assumptions regarding the timing of its deliverables. During the nine months ended September 30, 2019 and 2018, the Company recognized revenue under the agreement with Servier of approximately $4.4 million and $4.3 million, respectively. Deferred revenue related to the agreement with Servier amounted to $83.8 million and $88.6 million as of September 30, 2019 and December 31, 2018, respectively, of which $5.9 million and $5.8 million, respectively is included in current liabilities. No development or sales-based milestone payments were received during the nine months ended September 30, 2019 and 2018. Collaboration and License Agreement with Gilead On September 10, 2018, the Company and Gilead Sciences, Inc. (“Gilead”) entered into a collaboration and license agreement to develop genome editing tools to target viral DNA associated with Hepatitis B. Pursuant to the terms of the agreement, Gilead will receive an exclusive license to exploit the resulting synthetic nucleases and products that use them to treat Hepatitis B in humans (“development license”), and the Company is entitled to receive up to $40.0 million in research funding for early-stage R&D services, paid in semi-annual increments, over an initial three year term and development and commercial milestone payments of up to an aggregate of $445.0 million, consisting of up to $105.0 million in development milestone payments and up to $340.0 million in commercial milestone payments. The Company is also entitled to receive tiered royalties ranging from the high single digit percentages to the mid-teen percentages on worldwide net sales of the products developed through the term of the agreement, subject to customary potential reductions. Gilead is responsible for obtaining regulatory approvals and, upon completion of the collaboration, will assume sole responsibility for the development and commercialization of such gene editing therapies and products. The Company will provide technology transfer of its development know-how prior to Gilead assuming responsibility. Also, the Company and Gilead will negotiate a separate supply agreement for the Company to manufacture specifically identified products for Gilead to use in clinical trials at price based on the Company’s costs. The Company and Gilead have formed a joint steering committee (“JSC”) and a joint research and development committee (“JRDC”) that collectively will provide oversight, decision making and implementation guidance regarding the collaboration activities covered under the agreement. The Company assessed this arrangement in accordance with ASC 606 and concluded that the promises in the agreement represent transactions with a customer. The Company has concluded that the agreement with Gilead contains the following promises: (i) a development license; (ii) performance of early-stage R&D services, including technology transfer services, iii) JSC and JRDC participation, and (iv) regulatory responsibilities related to non-clinical and chemistry, manufacturing and control (“CMC”) reports. The Company determined that the license and R&D services were not distinct from each other, as the license and R&D services are highly interdependent upon one another. Participation on the JSC and JRDC to oversee the research and development activities are combined into the single performance obligation as these activities are highly interdependent with the other R&D services. The regulatory responsibilities related to non-clinical and CMC filings do not represent separate performance obligations based on their dependence on the research and development efforts. As such, the Company determined that these promises should be combined into a single performance obligation. Under the agreement with Gilead, in order to evaluate the appropriate transaction price, the Company determined that the $40.0 million research funding for early-stage R&D services, paid in semi-annual increments over an initial three-year term, constituted the entire consideration to be included in the transaction price as of the outset of the arrangement. As such, this amount was allocated to the single performance obligation. The potential development and commercial milestone payments that the Company is eligible to receive were excluded from the transaction price, as all milestone amounts were fully constrained based on the probability of achievement, since the milestones relate to successful achievement of certain developmental goals, which might not be achieved. None of the future royalty payments were included in the transaction price, as the potential payments represent sales-based consideration. The Company will reevaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur, and, if necessary, adjust its estimate of the transaction price. Revenue associated with the combined performance obligation is being recognized as revenue on a straight-line basis as the R&D services are provided over the initial three-year term. The transfer of control occurs over this time period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. During the nine months ended September 30, 2019 and 2018, the Company recognized revenue under the agreement with Gilead of approximately $10.0 million and $0.7 million, respectively. Deferred revenue related to the agreement with Gilead amounted to $4.9 million and $2.3 million as of September 30, 2019 and December 31, 2018, respectively, of which $4.9 million and $2.3 million, respectively is included in current liabilities. No development or sales-based milestone payments were received during the nine months ended September 30, 2019.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
SEGMENT REPORTING	NOTE 9 : SEGMENT REPORTING The Company has developed a genome editing platform and performed related research for human therapeutic and agricultural applications. The Company’s Chief Operating Decision Maker (“CODM”) evaluates the Company’s financial performance based on two reportable segments: Therapeutics and Food. The Therapeutics segment is focused on the development of products in the field of immuno-oncology and of novel products outside immuno-oncology to treat human diseases. The Food segment is focused on applying ARCUS to develop food and nutrition products through collaboration agreements with consumer-facing companies. The CODM reviews segment performance and allocates resources based upon segment revenue and segment operating loss of the Therapeutics and Food reportable segments. Segment operating loss is derived by deducting operational cash expenditures, net, from GAAP revenue. Operational cash expenditures are cash disbursements made that are directly attributable to the reportable segment (including directly attributable research and development and property, equipment, and software expenditures). For the nine months ended September 30, 2018, the Company allocated centralized research and development expenditures for early stage research, nuclease development and the purchase of general laboratory supplies to the Therapeutics and Food segments based on headcount. In January 2019, the Food segment moved into a new leased facility at Research Triangle Park, North Carolina. The Company has determined that the Food segment is no longer deriving benefit from the Company’s centralized research and development expenditures, thus all these expenditures are allocated to the Therapeutics segment for the nine months ended September 30, 2019. The reportable segment and centralized research and development operational cash expenditures include cash disbursements for compensation, laboratory supplies, purchases of property, equipment, and software and procuring services from CROs, CMOs, and research organizations. Certain cost items are not allocated to the Company’s reportable segments. These cost items primarily consist of compensation and general operational expenses associated with the Company’s executive, business development, finance, operations, human resources and legal functions. The Company does not allocate non-cash income statement amounts to its reportable segments, such as share based compensation, depreciation and amortization, intangible asset impairment charges, non-cash interest expense and losses on the disposal of assets. When reconciling segment operating loss to consolidated loss from operations, the Company makes an adjustment to convert the cash expenditures to the accrual basis to reflect GAAP. All segment revenue is earned in the United States and there are no intersegment revenues. Additionally, the Company reports assets on a consolidated basis and does not allocate assets to its reportable segments for purposes of assessing segment performance or allocating resources. Presented below is the financial information with respect to the Company’s reportable segments: Three Months Ended September 30, (in thousands) 2019 2018 Revenue: Therapeutics $ 4,719 $ 2,115 Food 146 426 Total segment revenue 4,865 2,541 Segment operational cash expenditures: Therapeutics $ 14,290 $ 11,727 Food 1,942 857 Total segment operational cash expenditures 16,232 12,584 Allocation of centralized research and development operational cash expenditures: Therapeutics $ 4,081 $ 2,387 Food — 597 Total allocation of centralized research and development operational cash expenditures 4,081 2,984 Segment operating loss: Therapeutics $ (13,652 ) $ (11,999 ) Food (1,796 ) (1,028 ) Total segment operating loss (15,448 ) (13,027 ) Adjustments to reconcile segment operating loss to consolidated loss from operations: Corporate general and administrative cash expenditures $ (6,581 ) $ (3,719 ) Interest income received (1,236 ) (691 ) Depreciation and amortization (1,401 ) (584 ) Share-based compensation (2,491 ) (292 ) Changes in prepaid expenses, accounts payable and accrued expenses 5,179 7,866 Total consolidated loss from operations $ (21,978 ) $ (10,447 ) Nine Months Ended September 30, (in thousands) 2019 2018 Revenue: Therapeutics $ 14,357 $ 5,009 Food 1,359 934 Total segment revenue 15,716 5,943 Segment operational cash expenditures: Therapeutics $ 42,072 $ 25,903 Food 6,126 2,590 Total segment operational cash expenditures 48,198 28,493 Allocation of centralized research and development operational cash expenditures: Therapeutics $ 10,952 $ 6,329 Food — 1,830 Total allocation of centralized research and development operational cash expenditures 10,952 8,159 Segment operating loss: Therapeutics $ (38,667 ) $ (27,223 ) Food (4,767 ) (3,486 ) Total segment operating loss (43,434 ) (30,709 ) Adjustments to reconcile segment operating loss to consolidated loss from operations: Corporate general and administrative cash expenditures $ (24,726 ) $ (8,397 ) Interest income received (3,322 ) (1,213 ) Depreciation and amortization (3,508 ) (1,555 ) Share-based compensation (6,319 ) (697 ) Loss on disposal of assets (22 ) (8 ) Changes in prepaid expenses, accounts payable and accrued expenses 15,988 10,772 Total consolidated loss from operations $ (65,343 ) $ (31,807 )

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Revenue Recognition for Contracts with Customers	Revenue Recognition for Contracts with Customers The Company’s revenues are generated primarily through collaborative research, license, development and commercialization agreements. Effective January 1, 2019, the Company adopted Accounting Standards Update (“ASU”) No. 2014-09, Revenue: Revenue from Contracts with Customers Revenue Recognition At contract inception, once the contract is determined to be within the scope of ASC 606, the Company evaluates the performance obligations promised in the contract that are based on goods and services that will be transferred to the customer and determines whether those obligations are both (i) capable of being distinct and (ii) distinct in the context of the contract. Goods or services that meet these criteria are considered distinct performance obligations. If both these criteria are not met, the goods and services are combined into a single performance obligation. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, these options are considered performance obligations. The exercise of a material right is accounted for as a contract modification for accounting purposes. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue within current liabilities in the accompanying condensed consolidated balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue – noncurrent. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets in the Other current assets line item in the condensed consolidated balance sheets. Milestone Payments – If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. Royalties – For arrangements that include sales-based royalties, including milestone payments based on a level of sales, which are the result of a customer-vendor relationship and for which the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied or partially satisfied. To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. Significant Financing Component – In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed each of its revenue arrangements in order to determine whether a significant financing component exists and concluded that a significant financing component does not exist in any of its arrangements. Collaborative Arrangements – The Company has entered into collaboration agreements, which are within the scope of ASC 606, to discover, develop, manufacture and commercialize product candidates. The terms of these agreements typically contain multiple promises or obligations, which may include: (1) licenses, or options to obtain licenses, to use the Company’s technology, (2) research and development activities to be performed on behalf of the collaboration partner, and (3) in certain cases, services in connection with the manufacturing of preclinical and clinical material. Payments the Company receives under these arrangements typically include one or more of the following: non-refundable, upfront license fees; option exercise fees; funding of research and/or development efforts; clinical and development, regulatory, and sales milestone payments; and royalties on future product sales. The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808, Collaborative Arrangements For a complete discussion of accounting for collaboration revenues, see Note 8, “Collaboration and license agreements.”
Recent Accounting Pronouncements	Recent Accounting Pronouncements As a result of adopting ASC 606, the Company recorded a $1.0 million transition adjustment to reduce the opening balance of accumulated deficit in the first quarter of 2019 primarily as a result of the treatment of the up-front consideration received from the Company’s collaboration agreements under superseded prior revenue recognition guidance. A summary of the amount by which each financial statement line item was affected by the impact of the cumulative adjustment is set forth in the table below: Impact of ASC 606 Adoption on Condensed Consolidated Balance Sheet as of January 1, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Deferred revenue - current liabilities $ 8,029 $ 407 $ 8,436 Deferred revenue - noncurrent liabilities 82,217 590 82,807 Accumulated deficit (84,190 ) (997 ) (85,187 ) A summary of the amount by which each financial statement line item was affected in the current reporting period by ASC 606 as compared with the guidance that was in effect prior to adoption is set forth in the tables below: Impact of ASC 606 Adoption on Condensed Consolidated Balance Sheet as of September 30, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Deferred revenue - current liabilities 10,767 1,433 12,200 Deferred revenue - noncurrent liabilities 77,887 888 78,775 Accumulated deficit (156,151 ) 2,321 (153,830 ) Impact of ASC 606 Adoption on Condensed Consolidated Statement of Operations for the Three Months Ended September 30, 2019 Impact of ASC 606 Adoption on Condensed Consolidated Statement of Operations for the Nine Months Ended September 30, 2019 (in thousands, except per share data) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Revenue $ 4,865 $ (218 ) $ 4,647 $ 15,716 $ (1,324 ) $ 14,392 Net loss (20,742 ) (218 ) (20,960 ) (71,961 ) (1,324 ) (73,285 ) Net loss per share - basic and diluted (0.41 ) (0.00 ) (0.41 ) (1.85 ) (0.03 ) (1.88 ) Impact of ASC 606 Adoption on Condensed Consolidated Statement of Cash Flows for the Nine Months Ended September 30, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Net loss $ (71,961 ) $ (1,324 ) $ (73,285 ) Changes in deferred revenue (1,592 ) 1,324 (268 ) During the nine months ended September 30, 2019, the Company recorded $6.4 million in revenue that was included in deferred revenue as of December 31, 2018. The most significant change to the Company’s revenue recognition as a result of the adoption of ASC 606 relates to the accounting for certain option fees and milestone payments in determining the transaction price (step (iii)), and the revenue recognition pattern (step (v)) related to the Company’s development and commercial license agreement with Laboratoires Servier (“Servier”) (see Note 8). Under ASC 605, the option fees payable by the Company to exercise the 50/50 co-development and co-promotion option was accounted for as a reduction in the arrangement consideration, and certain development milestones that may be earned for early-stage pre-IND development milestones were included in the arrangement consideration as the early-stage pre-IND development milestones were deemed to be non-substantive. Under ASC 606, the option fees were not accounted for as a reduction in the transaction price as the option fees are contingent upon Servier’s exercise of its commercial (customer) options on licensed product candidates, and the milestone payments were excluded from the transaction price based on the assessment of the most likely amount and application of the variable consideration constraint, since the milestones relate to successful achievement of certain developmental goals, which might not be achieved. In addition, under ASC 605, the Company recognized revenue on a straight‑line basis over the period the Company expected to complete its obligations. Under ASC 606, the Company recognizes revenue based on the proportional performance of the services related to the performance obligation expected. For further discussion of the adoption of ASC 606 see Note 8, “Collaboration and license agreements.” Collaborative Arrangements (Topic 808)—Clarifying the Interaction between Topic 808 and ASC 606 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) Leases, Targeted Improvements to ASC 842, Leases , Leases The Company is currently evaluating the potential impact ASU 2016-02 may have on its financial position, results of operations, and related footnotes. The Company expects it will elect to utilize the available package of practical expedients permitted under the transition guidance within the new standard, which does not require the reassessment of the following: i) whether existing or expired arrangements are or contain a lease, ii) the lease classification of existing or expired leases, and iii) whether previous initial direct costs would qualify for capitalization under the new lease standard.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Impact of Adopting Topic 606 on Condensed Financial Statements	A summary of the amount by which each financial statement line item was affected by the impact of the cumulative adjustment is set forth in the table below: Impact of ASC 606 Adoption on Condensed Consolidated Balance Sheet as of January 1, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Deferred revenue - current liabilities $ 8,029 $ 407 $ 8,436 Deferred revenue - noncurrent liabilities 82,217 590 82,807 Accumulated deficit (84,190 ) (997 ) (85,187 ) A summary of the amount by which each financial statement line item was affected in the current reporting period by ASC 606 as compared with the guidance that was in effect prior to adoption is set forth in the tables below: Impact of ASC 606 Adoption on Condensed Consolidated Balance Sheet as of September 30, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Deferred revenue - current liabilities 10,767 1,433 12,200 Deferred revenue - noncurrent liabilities 77,887 888 78,775 Accumulated deficit (156,151 ) 2,321 (153,830 ) Impact of ASC 606 Adoption on Condensed Consolidated Statement of Operations for the Three Months Ended September 30, 2019 Impact of ASC 606 Adoption on Condensed Consolidated Statement of Operations for the Nine Months Ended September 30, 2019 (in thousands, except per share data) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Revenue $ 4,865 $ (218 ) $ 4,647 $ 15,716 $ (1,324 ) $ 14,392 Net loss (20,742 ) (218 ) (20,960 ) (71,961 ) (1,324 ) (73,285 ) Net loss per share - basic and diluted (0.41 ) (0.00 ) (0.41 ) (1.85 ) (0.03 ) (1.88 ) Impact of ASC 606 Adoption on Condensed Consolidated Statement of Cash Flows for the Nine Months Ended September 30, 2019 (in thousands) As reported under ASC 606 Adjustments Balances without adoption of ASC 606 Net loss $ (71,961 ) $ (1,324 ) $ (73,285 ) Changes in deferred revenue (1,592 ) 1,324 (268 )

Stock Options (Tables)

Stock Options (Tables)	9 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock-Based Compensation Expense	The Company recorded employee and nonemployee share-based compensation expense as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Employee $ 2,328 $ 292 $ 5,905 $ 690 Nonemployee 163 - 414 7 $ 2,491 $ 292 $ 6,319 $ 697
Schedule of Stock-Based Compensation Expense	Share-based compensation expense related to stock options is included in the following line items in the condensed Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Research and development $ 1,615 $ 224 $ 4,131 $ 502 General and administrative 876 68 2,188 195 $ 2,491 $ 292 $ 6,319 $ 697
Schedule of Stock Options Valuation Assumptions Using a Black-Scholes Option Pricing Model	The Company granted 2,115,331 stock options for the nine months ended September 30, 2019. The fair value of each stock option grant is estimated using a Black-Scholes option-pricing model on the date of grant as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2019 Estimated dividend yield 0.00 % 0.00 % Weighted-average expected stock price volatility 68.13 % 68.16 % Weighted-average risk-free interest rate 1.74 % 2.08 % Expected life of options (in years) 6.81 6.60 Weighted-average fair value per option $ 7.57 $ 8.20
Summary of Activity of Option Plans	The following table summarizes activity in the Company’s stock option plans for the nine months ended September 30, 2019: Outstanding Option Shares Weighted- Average Exercise Price Balance as of January 1, 2019 7,763,464 $ 5.00 Granted 2,115,331 12.48 Exercised (445,408 ) 0.99 Forfeited/canceled (385,757 ) 10.46 Balance as of September 30, 2019 9,047,630 6.72

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	The following is a schedule of future minimum lease payments for all leases as of September 30, 2019 (in thousands): Operating Leases Remainder of 2019 $ 659 2020 2,690 2021 2,635 2022 2,718 2023 2,795 2024 and beyond 3,742

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
Schedule of Assets Measured at Fair Value on Recurring Basis	The following represents assets measured at fair value on a recurring basis by the Company (in thousands): September 30, 2019 Fair Value Level 1 Level 2 Level 3 Assets: Money market funds $ 1,227 $ 1,227 $ — $ — Repurchase agreements 201,000 — 201,000 — $ 202,227 $ 1,227 $ 201,000 $ — December 31, 2018 Fair Value Level 1 Level 2 Level 3 Assets: Money market funds $ 781 $ 781 $ — $ — Repurchase agreements 94,500 — 94,500 — $ 95,281 $ 781 $ 94,500 $ —

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Financial Information with Respect to Company's Reportable Segments	Presented below is the financial information with respect to the Company’s reportable segments: Three Months Ended September 30, (in thousands) 2019 2018 Revenue: Therapeutics $ 4,719 $ 2,115 Food 146 426 Total segment revenue 4,865 2,541 Segment operational cash expenditures: Therapeutics $ 14,290 $ 11,727 Food 1,942 857 Total segment operational cash expenditures 16,232 12,584 Allocation of centralized research and development operational cash expenditures: Therapeutics $ 4,081 $ 2,387 Food — 597 Total allocation of centralized research and development operational cash expenditures 4,081 2,984 Segment operating loss: Therapeutics $ (13,652 ) $ (11,999 ) Food (1,796 ) (1,028 ) Total segment operating loss (15,448 ) (13,027 ) Adjustments to reconcile segment operating loss to consolidated loss from operations: Corporate general and administrative cash expenditures $ (6,581 ) $ (3,719 ) Interest income received (1,236 ) (691 ) Depreciation and amortization (1,401 ) (584 ) Share-based compensation (2,491 ) (292 ) Changes in prepaid expenses, accounts payable and accrued expenses 5,179 7,866 Total consolidated loss from operations $ (21,978 ) $ (10,447 ) Nine Months Ended September 30, (in thousands) 2019 2018 Revenue: Therapeutics $ 14,357 $ 5,009 Food 1,359 934 Total segment revenue 15,716 5,943 Segment operational cash expenditures: Therapeutics $ 42,072 $ 25,903 Food 6,126 2,590 Total segment operational cash expenditures 48,198 28,493 Allocation of centralized research and development operational cash expenditures: Therapeutics $ 10,952 $ 6,329 Food — 1,830 Total allocation of centralized research and development operational cash expenditures 10,952 8,159 Segment operating loss: Therapeutics $ (38,667 ) $ (27,223 ) Food (4,767 ) (3,486 ) Total segment operating loss (43,434 ) (30,709 ) Adjustments to reconcile segment operating loss to consolidated loss from operations: Corporate general and administrative cash expenditures $ (24,726 ) $ (8,397 ) Interest income received (3,322 ) (1,213 ) Depreciation and amortization (3,508 ) (1,555 ) Share-based compensation (6,319 ) (697 ) Loss on disposal of assets (22 ) (8 ) Changes in prepaid expenses, accounts payable and accrued expenses 15,988 10,772 Total consolidated loss from operations $ (65,343 ) $ (31,807 )

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 01, 2019	Mar. 15, 2019	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Date of incorporation				Jan. 26, 2006
issuance costs				$ 2,507	$ 481
Stockholders' equity, reverse stock split		1-for-2.134686
Preferred stock, shares outstanding				0
Transition adjustment to opening balance of accumulated deficit				$ (156,151)		$ (84,190)	$ (85,187)
Revenue recorded included in deferred revenue				6,400
ASU 2014-09 | Adjustments
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Transition adjustment to opening balance of accumulated deficit				$ 2,321		$ (997)
Common Stock
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock upon conversion of convertible notes, shares			2,921,461
Initial Public Offering ("IPO") | Series A and Series B Convertible Preferred Stock
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Preferred stock, shares outstanding	0
Initial Public Offering ("IPO") | Common Stock
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Shares issued and sold	9,085,000
Shares issued and sold, public offering price	$ 16
Proceeds from issuance, net of underwriting discounts, commissions and issuance cost	$ 130,500
Underwriting discount and commission	10,200
issuance costs	$ 4,600
Initial Public Offering ("IPO") | Common Stock | Convertible Notes Payable (2019 Notes)
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock upon conversion of convertible notes, shares	2,921,461
Initial Public Offering ("IPO") | Common Stock | Series A and Series B Convertible Preferred Stock
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock upon conversion of convertible notes, shares	22,301,190
Precision PlantSciences, Inc.
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Date of incorporation				Jan. 4, 2012
Percentage owned in subsidiary				100.00%
Amended date of incorporation				Jan. 16, 2018
Amended name of incorporation				Elo Life Systems, Inc
Elo Life Systems Australia Pty Ltd | Subsidiary Issuer
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Date of incorporation				May 29, 2018
Percentage owned in subsidiary				100.00%
Precision BioSciences UK Limited
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Date of incorporation				Jun. 17, 2019
Percentage owned in subsidiary				100.00%

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies - Summary of Impact of Adopting Topic 606 on Condensed Financial Statements - Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue - current liabilities	$ 10,767	$ 8,029
Deferred revenue - noncurrent liabilities	77,887	82,217
Accumulated deficit	(156,151)	(84,190)	$ (85,187)
ASU 2014-09 | Adjustments
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue - current liabilities	1,433	407
Deferred revenue - noncurrent liabilities	888	590
Accumulated deficit	2,321	(997)
ASU 2014-09 | Balances without adoption of ASC 606
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue - current liabilities	12,200	8,436
Deferred revenue - noncurrent liabilities	78,775	82,807
Accumulated deficit	$ (153,830)	$ (85,187)

Description of Business and S_6

Description of Business and Summary of Significant Accounting Policies - Summary of Impact of Adopting Topic 606 on Condensed Financial Statements - Condensed Consolidated Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 4,865			$ 2,541			$ 15,716	$ 5,943
Net loss	$ (20,742)	$ (19,436)	$ (31,783)	$ (9,756)	$ (11,826)	$ (9,012)	$ (71,961)	$ (30,594)
Net loss per share attributable to common stockholders- basic and diluted	$ (0.41)			$ (0.62)			$ (1.85)	$ (1.94)
ASU 2014-09 | Adjustments
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ (218)						$ (1,324)
Net loss	$ (218)						$ (1,324)
Net loss per share attributable to common stockholders- basic and diluted	$ 0						$ (0.03)
ASU 2014-09 | Balances without adoption of ASC 606
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 4,647						$ 14,392
Net loss	$ (20,960)						$ (73,285)
Net loss per share attributable to common stockholders- basic and diluted	$ (0.41)						$ (1.88)

Description of Business and S_7

Description of Business and Summary of Significant Accounting Policies - Summary of Impact of Adopting Topic 606 on Condensed Financial Statements - Condensed Consolidated Statement of of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	$ (71,961)	$ (30,594)
Changes in deferred revenue	(1,592)	$ 1,296
ASU 2014-09 | Adjustments
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	(1,324)
Changes in deferred revenue	1,324
ASU 2014-09 | Balances without adoption of ASC 606
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	(73,285)
Changes in deferred revenue	$ (268)

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - $ / shares	Apr. 01, 2019	Jun. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Stockholders' Equity [Line Items]
Preferred stock, shares outstanding			0
Common and prferred stocks, shares authorized	210,000,000
Common stock, shares authorized	200,000,000		200,000,000	130,000,000
Common stock, par value	$ 0.000005		$ 0.000005	$ 0.000005
Preferred stock, shares authorized	10,000,000		10,000,000	0
Preferred stock, par value	$ 0.0001		$ 0.0001	$ 0.0001
Common Stock
Stockholders' Equity [Line Items]
Common stock issued upon conversion of convertible preferred stock or convertible promissory notes		2,921,461
Initial Public Offering ("IPO") | Series A and Series B Convertible Preferred Stock
Stockholders' Equity [Line Items]
Preferred stock, shares outstanding	0
Initial Public Offering ("IPO") | Common Stock | Convertible Notes Payable (2019 Notes)
Stockholders' Equity [Line Items]
Common stock issued upon conversion of convertible preferred stock or convertible promissory notes	2,921,461
Initial Public Offering ("IPO") | Common Stock | Series A and Series B Convertible Preferred Stock
Stockholders' Equity [Line Items]
Common stock issued upon conversion of convertible preferred stock or convertible promissory notes	22,301,190

Stock Options - Additional Info

Stock Options - Additional Information (Details) - USD ($) $ in Millions	Mar. 12, 2019	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	May 31, 2018	Dec. 31, 2016	Apr. 30, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding		9,047,630	7,763,464
Stock options outstanding		2,115,331
Unrecognized compensation cost		$ 30.3
Weighted-average period for recognition of compensation cost		3 years 1 month 9 days
Intrinsic value of Stock options exercised		$ 5.3		$ 1
2006 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining shares available to be granted						0
Options outstanding		1,397,203
2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding		6,111,373
Common stock reserved for issuance					8,211,980		5,270,095
2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	4,750,000
Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock	4.00%
Maximum shares of common stock may be issued	5,000,000
Stock options outstanding		1,539,054
2019 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	525,000
Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock	1.00%
Maximum shares allowed to be issued under ESPP	5,250,000
Purchase of common stock through payroll deductions expressed in percentage of fair market value	85.00%
Offering period commenced date	Oct. 21, 2019
Offering period end date	Feb. 29, 2020

Stock Options - Schedule of Emp

Stock Options - Schedule of Employee and Nonemployee Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 2,491	$ 292	$ 6,319	$ 697
Employee
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	2,328	$ 292	5,905	690
Nonemployee
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 163		$ 414	$ 7

Stock Options - Schedule of Sto

Stock Options - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 2,491	$ 292	$ 6,319	$ 697
Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	2,491	292	6,319	697
Research and Development | Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	1,615	224	4,131	502
General and Administrative | Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 876	$ 68	$ 2,188	$ 195

Stock Options - Schedule of S_2

Stock Options - Schedule of Stock Options Valuation Assumptions Using a Black-Scholes Option Pricing Model (Details) - $ / shares	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Estimated dividend yield	0.00%	0.00%
Weighted-average expected stock price volatility	68.13%	68.16%
Weighted-average risk-free interest rate	1.74%	2.08%
Expected life of options (in years)	6 years 9 months 21 days	6 years 7 months 6 days
Weighted-average fair value per option	$ 7.57	$ 8.20

Stock Options - Summary of Acti

Stock Options - Summary of Activity of Option Plans (Details)	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding Option Shares, Beginning Balance | shares	7,763,464
Stock options outstanding | shares	2,115,331
Option, Exercised | shares	(445,408)
Option, Forfeited/canceled | shares	(385,757)
Outstanding Option Shares, Ending Balance | shares	9,047,630
Weighted-Average Exercise Price Outstanding at Beginning Balance | $ / shares	$ 5
Weighted-Average Exercise Price, Granted | $ / shares	12.48
Weighted-Average Exercise Price, Exercised | $ / shares	0.99
Weighted-Average Exercise Price, Forfeited/canceled | $ / shares	10.46
Weighted-Average Exercise Price Outstanding at Ending Balance | $ / shares	$ 6.72

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Future Lease Payments (Details) $ in Thousands	Sep. 30, 2019USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
Remainder of 2019	$ 659
2020	2,690
2021	2,635
2022	2,718
2023	2,795
2024 and beyond	$ 3,742

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Details)	9 Months Ended
	Sep. 30, 2019
Maximum
Commitments And Contingencies [Line Items]
Agreement termination notice period	1 year

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 01, 2019	May 31, 2019	Jun. 30, 2019	Sep. 30, 2019	Mar. 31, 2019
Debt Instrument [Line Items]
Change in fair value of convertible note payable				$ 9,758
Revolving Line [Member] | Pacific Western Loan Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 50,000
Maturity of line of credit		May 15, 2022
Required daily balance of cash in demand deposits accounts				$ 25,000
Revolving line, fee percentage				0.50%
Borrowings				$ 0
Revolving Line [Member] | Revolving Line If Daily Balance Is Maintained [Member] | Prime Rate [Member] | Pacific Western Loan Agreement [Member]
Debt Instrument [Line Items]
Basis point deducted from the prime rate				1.25%
Interest rate during period				4.25%
Revolving Line [Member] | Revolving Line If Daily Balance Is Not Maintained [Member] | Prime Rate [Member] | Pacific Western Loan Agreement [Member]
Debt Instrument [Line Items]
Interest rate during period				5.75%
Basis point added to the prime rate				0.25%
Common Stock
Debt Instrument [Line Items]
Number of common stock issued upon settlement convertible promissory notes			2,921,461
Convertible Notes Payable (2019 Notes)
Debt Instrument [Line Items]
Aggregate principal amount					$ 39,600
Notes accrued interest rate				6.00%
Settlement price equal on IPO price per Share				85.00%
Settlement Price Per Share				$ 13.60
Fair value of notes	$ 49,400
Change in fair value of convertible note payable				$ 9,800
Interest expense				$ 200
Convertible Notes Payable (2019 Notes) | Initial Public Offering ("IPO") | Common Stock
Debt Instrument [Line Items]
Number of common stock issued upon settlement convertible promissory notes	2,921,461

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019
Income Tax Disclosure [Line Items]
Unrecognized income tax benefits		$ 0
Forecast
Income Tax Disclosure [Line Items]
Effective income tax rate	0.00%

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	$ 202,227	$ 95,281
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	1,227	781
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	201,000	94,500
Repurchase Agreements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	201,000	94,500
Repurchase Agreements | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	201,000	94,500
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	1,227	781
Money Market Funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	$ 1,227	$ 781

Collaboration and License Agr_2

Collaboration and License Agreements - Additional Information (Details) - USD ($)	Sep. 10, 2018	Feb. 24, 2016	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Collaboration and License Agreements [Line items]
Revenue recorded included in deferred revenue			$ 6,400,000
Deferred revenue			10,767,000		$ 8,436,000
Development and Commercial License Agreement | Servier
Collaboration and License Agreements [Line items]
Upfront payment		$ 105,000,000
Revenue recorded included in deferred revenue			4,400,000	$ 4,300,000
Deferred revenue			83,800,000		88,600,000
Development or sales-based milestone payments			0	0
Development and Commercial License Agreement | Servier | Current Liabilities
Collaboration and License Agreements [Line items]
Deferred revenue			5,900,000		5,800,000
Development and Commercial License Agreement | Servier | Maximum
Collaboration and License Agreements [Line items]
Total payments to be received		1,600,000,000
Aggregate milestone payments		1,500,000,000
Development milestone payments		401,300,000
Commercial milestone payments		$ 1,100,000,000
Collaboration and License Agreement | Gilead
Collaboration and License Agreements [Line items]
Revenue recorded included in deferred revenue			10,000,000	$ 700,000
Deferred revenue			4,900,000		2,300,000
Development or sales-based milestone payments			$ 0
Research funding payment term	3 years		3 years
Semi-annual research funding payments	$ 40,000,000
Collaboration and License Agreement | Gilead | Current Liabilities
Collaboration and License Agreements [Line items]
Deferred revenue			$ 4,900,000		$ 2,300,000
Collaboration and License Agreement | Gilead | Maximum
Collaboration and License Agreements [Line items]
Development milestone payments	105,000,000
Commercial milestone payments	340,000,000
Receivable from research funding	40,000,000
Development and commercial milestone payments	$ 445,000,000

Collaboration and License Agr_3

Collaboration and License Agreements - Additional Information (Details 1 ) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01 $ in Millions	Feb. 24, 2016USD ($)
Collaboration and License Agreements [Line items]
Revenue from upfront payment	$ 105
Estimated period performance obligation	7 years

Segment Reporting - Additional

Segment Reporting - Additional Information (Details)	9 Months Ended
	Sep. 30, 2019Segment
Segment Reporting [Abstract]
Number of reportable segments	2

Segment Reporting - Financial I

Segment Reporting - Financial Information with Respect to Company's Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Revenue	$ 4,865	$ 2,541	$ 15,716	$ 5,943
Total allocation of centralized research and development operational cash expenditures	19,791	9,737	62,512	28,723
Loss from operations	(21,978)	(10,447)	(65,343)	(31,807)
Adjustments to reconcile segment operating loss to consolidated loss from operations:
Interest income received	(1,236)	(691)	(3,322)	(1,213)
Depreciation and amortization			(3,508)	(1,555)
Share-based compensation			(6,319)	(697)
Loss on disposal of assets			(22)	(8)
Changes in prepaid expenses, accounts payable and accrued expenses	5,179	7,866	15,988	10,772
Operating Segments
Segment Reporting Information [Line Items]
Revenue	4,865	2,541	15,716	5,943
Total segment operational cash expenditures	16,232	12,584	48,198	28,493
Total allocation of centralized research and development operational cash expenditures	4,081	2,984	10,952	8,159
Loss from operations	(15,448)	(13,027)	(43,434)	(30,709)
Operating Segments | Therapeutics
Segment Reporting Information [Line Items]
Revenue	4,719	2,115	14,357	5,009
Total segment operational cash expenditures	14,290	11,727	42,072	25,903
Total allocation of centralized research and development operational cash expenditures	4,081	2,387	10,952	6,329
Loss from operations	(13,652)	(11,999)	(38,667)	(27,223)
Operating Segments | Food
Segment Reporting Information [Line Items]
Revenue	146	426	1,359	934
Total segment operational cash expenditures	1,942	857	6,126	2,590
Total allocation of centralized research and development operational cash expenditures		597		1,830
Loss from operations	(1,796)	(1,028)	(4,767)	(3,486)
Segment Reconciling Items
Adjustments to reconcile segment operating loss to consolidated loss from operations:
Corporate general and administrative cash expenditures	(6,581)	(3,719)	(24,726)	(8,397)
Interest income received	(1,236)	(691)	(3,322)	(1,213)
Depreciation and amortization	(1,401)	(584)	(3,508)	(1,555)
Share-based compensation	$ (2,491)	$ (292)	(6,319)	(697)
Loss on disposal of assets			$ (22)	$ (8)