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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2019	Mar. 02, 2020	Jun. 28, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Period Focus	FY
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		51,399,847
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 Annual Report	true
Document Transition Report	false
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Public Float			$ 589.0
Documents Incorporated by Reference	None

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 180,886	$ 103,193
Accounts receivable	965	523
Prepaid expenses	9,497	8,913
Other current assets	2,324	3,046
Total current assets	193,672	115,675
Property, equipment, and software—net	39,571	21,147
Intangible assets—net	1,432	1,466
Other assets	558	312
Total assets	235,233	138,600
Current liabilities:
Accounts payable	2,037	2,218
Accrued compensation	4,425	965
Accrued clinical and research and development expenses	2,400	1,569
Accrued other expenses and other current liabilities	1,584	887
Deferred revenue	16,486	8,436
Total current liabilities	26,932	14,075
Deferred revenue—noncurrent	65,895	82,807
Deferred rent—noncurrent	4,092	1,758
Total liabilities	96,919	98,640
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock
Additional paid-in capital	316,333	126,094
Accumulated deficit	(177,067)	(85,187)
Treasury stock	(952)	(952)
Total stockholders’ equity	138,314	39,960
Total liabilities and stockholders’ equity	$ 235,233	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

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Preferred stock, par value	$ 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
Common stock, shares authorized	200,000,000
Common stock, shares issued	51,965,708	16,717,117
Common stock, shares outstanding	51,155,236	15,906,645
Series A Convertible Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized		25,650,000
Preferred stock, shares issued	0	25,650,000
Preferred stock, shares outstanding	0	25,650,000
Series B Convertible Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized		21,956,100
Preferred stock, shares issued	0	21,956,095
Preferred stock, shares outstanding	0	21,956,095

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 22,238	$ 10,883
Operating expenses
Research and development	82,416	45,122
General and administrative	27,026	13,673
Total operating expenses	109,442	58,795
Loss from operations	(87,204)	(47,912)
Other income (expense), net:
Change in fair value of convertible notes payable	(9,758)
Interest expense	(182)
Interest income	4,267	1,875
Total other income (expense), net	(5,673)	1,875
Net loss and net loss attributable to common stockholders	$ (92,877)	$ (46,037)
Net loss per share attributable to common stockholders- basic and diluted	$ (2.21)	$ (2.92)
Weighted average shares of common stock outstanding- basic and diluted	41,991,162	15,775,541

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
Issuance of Series B convertible preferred stock, net of issuance costs	109,742		$ 2		109,740
Issuance of Series B convertible preferred stock, net of issuance costs, shares			21,956,095
Stock option exercises	$ 171				171
Stock option exercises, Shares	220,308			220,316
Share-based compensation expense	$ 2,453				2,492	(39)
Net loss	(46,037)					(46,037)
Ending balance at Dec. 31, 2018	39,960	$ 3	$ 2		126,094	(85,187)	(952)
Ending 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
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 payable	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	$ 1,261				1,261
Stock option exercises, Shares	940,940			940,940
Share-based compensation expense	$ 8,940				8,940
Net loss	(92,877)					(92,877)
Ending balance at Dec. 31, 2019	$ 138,314				$ 316,333	$ (177,067)	$ (952)
Ending balance, Shares at Dec. 31, 2019				51,965,708

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (92,877)	$ (46,037)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,317	2,354
Share-based compensation	8,940	2,453
Loss on disposal of property, equipment, and software	22	14
Non-cash interest expense	182
Change in fair value of convertible notes payable	9,758
Changes in operating assets and liabilities:
Prepaid expenses	(584)	(7,476)
Accounts receivable	(441)	(523)
Other assets and other current assets	1,032	(448)
Accounts payable	667	(673)
Accrued other expenses and other current liabilities	4,835	1,790
Deferred revenue	(7,866)	(3,177)
Net cash used in operating activities	(71,015)	(51,723)
Cash flows from investing activities:
Acquisition of license rights		(1,400)
Purchases of property, equipment and software	(24,666)	(14,278)
Proceeds from disposal of property, equipment, and software		15
Net cash used in investing activities	(24,666)	(15,663)
Cash flows from financing activities:
Proceeds from stock option exercises	1,261	171
Issuance of Series B convertible preferred stock, net of issuance costs		109,742
Deferred offering costs	(2,622)	(2,136)
Issuance of convertible notes payable	39,550
Proceeds from IPO, net of underwriting discounts and commissions	135,185
Net cash provided by financing activities	173,374	107,777
Net increase in cash and cash equivalents	77,693	40,391
Cash and cash equivalents—beginning of period	103,193	62,802
Cash and cash equivalents —end of period	180,886	103,193
Supplemental disclosures of noncash financing and investing activities:
Common stock issued on conversion of convertible notes payable	49,490
Property, equipment and software additions included in accounts payable, accrued expenses and other current liabilities	401	1,340
Deferred offering costs included in accounts payable, accrued expenses and other current liabilities	$ 168	$ 406

Description of Business and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 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. The Company’s 100% owned subsidiary, Precision BioSciences UK Limited, was incorporated on June 17, 2019. The accompanying 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 of its common stock at a public offering price of $16.00 per share and received approximately $130.5 million in net proceeds, after deducting underwriting discounts and commission of approximately $10.2 million and issuance costs of approximately $4.6 million.

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 notes payable, including accrued interest, were settled into 2,921,461 shares of common stock. Subsequent to the closing of the IPO, there were no shares of Series A or Series B convertible preferred stock or convertible notes payable outstanding.

Use of Estimates

The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and disclosures made in the accompanying notes to the consolidated financial statements. Actual results could differ from those estimates. Significant estimates include recording revenue for performance obligations recognized over time, determination of the fair value of share-based compensation grants and estimating services expended by third-party service providers used to recognize research and development expense.

Basis of Presentation

These financial statements have been prepared in accordance with GAAP. Additionally, the accompanying consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. As of December 31, 2019, the Company has not generated any revenue from product sales and does not expect to generate any revenue from the sale of product in the foreseeable future. During the year ended December 31, 2019, the Company incurred a net loss of $92.9 million and, as of December 31, 2019, has an accumulated deficit of $177.1 million. The Company has financed operations primarily through its IPO, private placements of convertible preferred stock and convertible debt and with proceeds from its development and commercial license agreement with Les Laboratoires Servier, (“Servier”) and Gilead Sciences, Inc. (“Gilead”) (see Note 12). The Company expects to incur additional operating losses and negative operating cash flows for the foreseeable future.

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 Consolidated Balance Sheet as of December 31, 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 Consolidated Balance Sheets.

Summary of Significant Accounting Policies

Cash and Cash Equivalents

The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. As of December 31, 2019 and December 31, 2018, the Company held cash equivalents composed of money market funds and repurchase agreements that were collateralized by deposits in the form of government securities and obligations.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents. All of the Company’s cash and cash equivalents are held at financial institutions that management believes to be of high credit quality. The Company may maintain cash deposits in financial institutions in excess of government insured limits. The Company regularly invests excess cash deposits in money market funds and repurchase agreements. The Company believes that the credit risk arising from the holdings of these financial instruments is mitigated by the fact that these securities are of short duration, government backed and of high credit rating. The Company has not experienced any losses on cash and cash equivalents to date.

Revenue from two development and license agreements accounted for 60% and 33% of revenue during 2019 and 34% and 53% of revenue during 2018, as well as 2% and 98% of deferred revenue as of December 31, 2019.

Deferred Equity Offering Costs

The Company capitalizes incremental legal, professional accounting and other third-party fees directly associated with the Company’s planned equity offerings as other current assets until the equity offering is consummated. After consummation, these costs are recorded in stockholders’ equity (deficit) as a reduction of additional paid-in capital. If the equity offering is not completed, any costs deferred will be expensed immediately.

Property, Equipment and Software

Property, equipment and software are stated at cost, net of depreciation and amortization. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the assets ranging from three to seven years. Leasehold improvements are amortized on a straight-line basis over the shorter of the lease term or estimated useful life of the asset.

The depreciation and amortization periods for the Company’s significant property, equipment and software categories are as follows:



Computer hardware and software	3 years
Lab equipment	5 to 7 years
Furniture and office equipment	3 to 5 years
Leasehold improvements	Lesser of remaining lease term or useful life

Repairs and maintenance are charged to operations as incurred, and expenditures for additions and improvements that extend the useful life of the asset are capitalized.

Intangible Assets

Intangible assets primarily include licenses and patents. The Company capitalizes license fees paid to acquire access to proprietary technology if the technology is expected to have alternative future use in multiple research and development projects. The cost of licensed technology rights is amortized using the straight-line method over the estimated useful life of the technology. If the access to use the technology rights is one year or less, the cost is recorded as a prepaid expense and amortized over the period identified in the agreement. Amortization expense for licensed technology and capitalized patent costs is included in research and development expenses within the accompanying consolidated statement of operations.

Impairment of Long-Lived Assets

Long-lived assets, such as property, equipment and software and intangible assets, subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment loss is assessed when future undiscounted cash flows are less than the assets’ carrying value and recognized when the carrying value of the asset exceeds fair value. Fair value is calculated by estimating the discounted future cash flows expected to be generated by the asset as well as other valuation techniques. An impairment charge is recognized for the amount by which the carrying amount exceeds the fair value of the asset.

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 from Contracts with Customers (“ASC 606”), using the modified retrospective transition method. Under this method, results for reporting periods beginning on January 1, 2019 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC Topic 605, Revenue Recognition (“ASC 605”). The Company applied the modified retrospective transition method to contracts that were not completed as of January 1, 2019. For the year ended December 31, 2019, the Company reduced revenue recognition by $1.4 million for changes in total estimated time to be incurred in the future to satisfy the performance obligation. ASC 606 applies to all contracts with customers, except for contracts that are within the scope of other standards. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation.

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 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 accompanying 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 or the licensee’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received and therefore revenue recognized is constrained as management is unable to assert that a reversal of revenue would not be possible. The transaction price is then allocated to each performance obligation on a relative standalone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenues and earnings in the period of adjustment.

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 linked to some or all of the royalty 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 the collaboration agreements are within the scope of accounting standards codification (“ASC”) ASC 808, Collaborative Arrangements (“ASC 808”) to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of ASC 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of ASC 808 and those that are more reflective of a vendor-customer relationship and, therefore, are within the scope of ASC 606. For elements of collaboration arrangements that are accounted for pursuant to ASC 808, an appropriate recognition method is determined and applied consistently, generally by analogy to ASC 606. For those elements of the arrangement that are accounted for pursuant to ASC 606, the Company applies the five-step model described above.

For additional discussion of accounting for collaboration revenues, see Note 12, “Collaboration and license agreements.”

Research and Development

Research and development costs are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities including salaries, benefits, share-based compensation, allocations for rent and facility costs, depreciation, preclinical manufacturing expenses, costs of services provided by contract research organizations (“CROs”) in connection with preclinical trials and contract manufacturing organizations (“CMOs”) engaged to manufacture clinical trial material, costs of licensing technology, and costs of services provided by research organizations and service providers. Upfront payments and milestone payments made for the licensing of technology are expensed as research and development in the period in which they are incurred if the technology is not expected to have any alternative future uses other than the specific research and development project for which it was intended. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed rather than when the payment is made.

The Company is required to estimate accrued research and development expenses resulting from its obligations under contracts with CROs, CMOs, research organizations, service providers, vendors and consultants in connection with research and development activities. The financial terms of these contracts are subject to negotiations and vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided to the Company under such contracts. The Company’s objective is to reflect the appropriate research and development expenses in its consolidated financial statements by matching those expenses with the period in which the services and efforts are expended. There may be instances in which payments made to the Company’s vendors will exceed the level of services provided and result in a prepayment of the expense. In accruing fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the Company’s estimate, the Company adjusts the accrual or amount of prepaid expense accordingly.

Although the Company does not expect its estimates to be materially different from amounts actually incurred, the Company’s understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in the Company reporting amounts that are too high or too low in any particular period. To date, the Company has not made any material adjustments to prior estimates of accrued research and development expenses.

Common Stock Valuation

Prior to the IPO, due to the absence of an active market for the Company’s common stock, the Company utilized methodologies in accordance with the framework of the American Institute of Certified Public Accountants Technical Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation, to estimate the fair value of its common stock. In determining the exercise prices for stock options granted prior to the IPO, the Company considered the estimated fair value of the common stock as of the measurement date. The estimated fair value of the common stock was determined based upon a variety of factors, including the illiquid nature of the common stock, the Company’s financial position and historical financial performance, the status of technological developments within the Company’s research, the composition and ability of the current research and management team, an evaluation or benchmark of the Company’s competition and the current business climate in the marketplace. Significant changes to the key assumptions underlying the factors used could result in different fair values of common stock at each valuation date.

Comprehensive Loss

Comprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders. For the years ended December 31, 2019 and December 31, 2018, there was no difference between net loss and comprehensive loss in the accompanying consolidated financial statements.

Net Loss Per Share

Basic net loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed using the weighted-average number of shares of common stock outstanding during the period and, if dilutive, the weighted-average number of potential shares of common stock. Diluted net loss per share is the same as basic net loss per share for the years ended December 31, 2019 and December 31, 2018 since all potential shares of common stock are anti-dilutive as a result of the net loss.

Share-Based Compensation

The Company accounts for all share-based compensation, including stock options and the employee stock purchase plan at fair value and recognizes compensation expense for those equity awards, net of actual forfeitures, over the requisite service period, which is generally the vesting period of the respective award.

The fair value of each equity grant is estimated on the date of grant using the Black-Scholes option-pricing model, which uses as inputs the fair value of the Company’s common stock and assumptions the Company makes for the volatility of its common stock, the expected term of the stock options, the risk-free interest rate for a period that approximates the expected term of the stock options and the Company’s expected dividend yield. As the Company has limited trading history, expected volatility is estimated based on the historical volatility of publicly traded peer companies and the Company expects to continue to do so until such time as it has adequate historical data regarding the volatility of our traded share price. The expected term of the options has been determined utilizing a weighted value considering actual history and estimated expected term based on the midpoint of final vest date and expiration date. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.

Income Taxes

Deferred tax assets and liabilities are determined based on the temporary differences between the consolidated financial statement carrying amounts and the tax basis of assets and liabilities using the enacted tax rates in effect in the years in which the differences are expected to reverse. In estimating future tax consequences, all expected future events are considered other than the enactment of changes in the tax law or rates. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes.

The Company may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement.

The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.

Accounting Standards Updates

The Company is an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, and may take advantage of reduced reporting requirements that are otherwise applicable to public companies. Section 107 of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies are required to comply with those standards. The Company has elected to use the extended transition period for complying with new or revised accounting standards. The JOBS Act also exempts the Company from having to provide an auditor attestation of internal controls over financial reporting under Sarbanes-Oxley Act Section 404(b).

The Company will remain an “emerging growth company” until the earliest of (i) December 31, 2024, (ii) the last day of the fiscal year in which it has total annual gross revenues of $1.07 billion or more, (iii) the date on which it has issued more than $1.0 billion in nonconvertible debt during the previous three years or (iv) the date on which it is deemed to be a large accelerated filer under the rules of the Securities and Exchange Commission (“SEC”), which generally is when it has more than $700 million in market value of its stock held by non-affiliates, has been a public company for at least 12 months and have filed one annual report on Form 10-K.

In May 2014, the Financial Accounting Standards Board, or FASB, issued ASC 606, which superseded the revenue requirements in ASC 605. In 2015 and 2016, the FASB issued additional ASUs related to ASC 606 that delayed the effective date of the guidance and clarified various aspects of the new revenue guidance, including principal versus agent considerations, identifying performance obligations, and licensing, and they include other improvements and practical expedients. Effective January 1, 2019, the Company adopted ASC 606 using the modified retrospective transition method.

As a result of adopting ASC 606, the Company recorded a $1.0 million transition adjustment in the first quarter of 2019 to reduce the opening balance of accumulated deficit as of January 1, 2019 primarily as a result of the treatment of the up-front consideration received from the Company’s collaboration agreements under 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 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 Consolidated Balance Sheet as of December 31, 2019
(in thousands)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Deferred revenue - current liabilities	$	16,486		$	(8,017	)	$	8,469
Deferred revenue - noncurrent liabilities		65,895			11,427			77,322
Accumulated deficit		(177,067	)		(3,410	)		(180,477	)

	Impact of ASC 606 Adoption on Consolidated Statement of Operations for the Years Ended December 31, 2019
(in thousands, except per share data)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Revenue	$	22,238		$	(2,413	)	$	19,825
Net loss		(92,877	)		(2,413	)		(95,290	)
Net loss per share - basic and diluted		(2.21	)		(0.06	)		(2.27	)

	Impact of ASC 606 Adoption on Consolidated Statement of Cash Flows for the Years Ended December 31, 2019
(in thousands)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Net loss	$	(92,877	)	$	(2,413	)	$	(95,290	)
Changes in deferred revenue		(7,866	)		2,413			(5,453	)

During the year ended December 31, 2019, the Company recorded $9.4 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 Servier. 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 may 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 12, “Collaboration and license agreements.”

In June 2018, the FASB issued ASU 2018-07, Compensation-Stock Compensation Improvements to Nonemployee Share-Based Payment Accounting (“ASU 2018-07”). ASU 2018-07 substantially aligns accounting for share-based payments to employees and non-employees. This ASU became effective for annual periods beginning after December 15, 2018 including interim periods within that period, and early adoption is permitted. The Company adopted ASU 2018-07 effective January 1, 2019. The adoption of the standard did not have a material impact on the Company’s consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). ASU 2018-13 is intended to improve the effectiveness of disclosures in the notes to financial statements related to fair value measurements in Topic 820. This ASU will become effective for annual periods beginning after December 15, 2019, including interim periods within that period, and early adoption is permitted. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements and related disclosures.

In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements (Topic 808)—Clarifying the Interaction between Topic 808 and ASC 606 (“ASU 2018-18”). The amendments in ASU 2018-18 make targeted improvements to GAAP for collaborative arrangements by clarifying that certain transactions between collaborative arrangement participants should be accounted for as revenue under ASC 606 when the collaborative arrangement participant is a customer in the context of a unit of account. In those situations, all the guidance in ASC 606 should be applied, including recognition, measurement, presentation, and disclosure requirements. In addition, unit-of-account guidance in ASU 2018-18 was aligned with the guidance in ASC 606 (that is, a distinct good or service) when an entity is assessing whether the collaborative arrangement or a part of the arrangement is within the scope of ASC 606. ASU 2018-18 is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption is permitted, including adoption in any interim period. The amendments should be applied retrospectively to the date of initial application of ASC 606. The Company adopted this guidance effective January 1, 2019 with its initial application of ASC 606. The adoption of the standard did not have an impact on the Company’s consolidated financial statements.

In November 2019, the FASB issued ASU 2019-10, Financial Instruments — Credit losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) (“ASU 2019-10”), which provides a one-year deferral of the effective dates of ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”), issued in February 2016. ASU 2016-02 was issued in order to improve comparability among organizations by recognizing lease assets and liabilities in the consolidated balance sheets for those leases previously classified as operating leases under GAAP. The update requires a lessee to recognize in its consolidated balance sheet a liability to make lease payments and also a right-of-use asset representing its right to use the underlying asset for the lease term. ASU 2019-10 is effective for fiscal years beginning after December 15, 2020 and interim periods within fiscal years beginning after December 15, 2021. The Company is currently evaluating the impact that this standard will have on its consolidated financial statements and expects to have an increase in total assets and total liabilities as a result of adopting the lease standard.

Other accounting standards updates issued, but not effective until after December 31, 2019, are not expected to have a material effect on the Company’s consolidated financial position, statements of operations or cash flows.

Property, Equipment and Software

12 Months Ended

Dec. 31, 2019

Property Plant And Equipment [Abstract]

PROPERTY, EQUIPMENT AND SOFTWARE

NOTE 2:

PROPERTY, EQUIPMENT AND SOFTWARE

Property, equipment and software consisted of the following as of December 31 (in thousands):

	2019		2018
Construction in progress	$	697	$	8,600
Leasehold improvements		25,969		5,733
Software		328		278
Laboratory equipment		19,251		10,057
Office equipment		1,602		839
Furniture and fixtures		2,373		1,124
Total property, equipment and software		50,220		26,631
Less accumulated depreciation and amortization		10,649		5,484
Property, equipment and software - net	$	39,571	$	21,147

In July 2019, we completed construction and opened our Manufacturing Center for Advanced Therapeutics, or MCAT, a manufacturing facility supporting our therapeutic product development platform, in a leased facility in Research Triangle Park. Of the $8.6 million construction-in-progress (CIP) balance as of December 31, 2018, $2.5 million related to the MCAT and $4.4 million related to our other leased facilities in Durham was recognized as leasehold improvements in the year ending December 31, 2019.

Depreciation expense, including amortization of leasehold improvements and software, was $5.3 million and $2.3 million for the years ended December 31, 2019 and December 31, 2018, respectively.

Intangible Assets

12 Months Ended

Dec. 31, 2019

Goodwill And Intangible Assets Disclosure [Abstract]

Intangible Assets

NOTE 3:

INTANGIBLE ASSETS

Intangible assets, net, consisted of the following as of December 31 (in thousands):

	2019			2018
License cost	$	1,831		$	1,831
Less: accumulated amortization		(281	)		(247	)
Less: impairments		(118	)		(118	)
Intangible assets, net		1,432			1,466

Amortization expense of the intangible assets was $0.1 million for the years ended December 31, 2019 and December 31, 2018.

In September 2018, the Company entered into a license agreement to obtain the rights to intellectual property for the production of biological materials for use in its development programs. The Company paid the licensor a one-time, non-refundable license fee of $1.4 million for rights to a cell line that can be used on up to four product candidates. The intellectual property rights are being amortized on a straight-line basis over a period of 216 to 257 months depending on the date the company adds product candidates to the agreement. Amortization expense will be approximately $0.1 million for each of the next five years with the remaining $0.9 million amortized to expense in 2025 and beyond.

Stockholders' Equity

12 Months Ended

Dec. 31, 2019

Stockholders Equity Note [Abstract]

Stockholders' Equity

NOTE 4:

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 notes payable, 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.

Share-Based Compensation

12 Months Ended

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

SHARE-BASED COMPENSATION

NOTE 5:

SHARE-BASED COMPENSATION

Under the terms of its equity incentive award plans, the Company’s board of directors may grant equity or equity-based awards to employees, directors and other 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 1,385,203 stock options outstanding under the 2006 Plan as of December 31, 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 5,462,954 stock options outstanding as of December 31, 2019. The Company’s board of directors determined 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, on or about March 14, 2019 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 provides for an annual increase to the number of shares of common stock available for issuance 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) 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. The number of shares available for issuance under the 2019 Plan was increased by 2,046,209 on January 1, 2020 pursuant to this provision. 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, will become available for award grants under the 2019 Plan. The 2019 Plan had 2,070,959 stock options outstanding as of December 31, 2019.

Up to 525,000 shares of the Company’s common stock were initially reserved for issuance under the 2019 ESPP. The 2019 ESPP provides for an annual increase to the number of shares available for issuance 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. The number of shares available for issuance under the 2019 ESPP was increased by 511,552 shares on January 1, 2020 pursuant to this provision. 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 ended on February 29, 2020; 44,197 shares were issued with respect to this offering period. The next ESPP offering period commenced on March 1, 2020 and will end on August 31, 2020.

The Company recorded employee and nonemployee share-based compensation expense as follows (in thousands):

	Years Ended December 31,
	2019		2018
Employee	$	8,354	$	2,431
Nonemployee		586		22
	$	8,940	$	2,453

Share-based compensation expense related to stock options is included in the following line items in the consolidated statements of operations (in thousands):

	Years Ended December 31,
	2019		2018
Research and development	$	5,639	$	1,817
General and administrative		3,301		636
	$	8,940	$	2,453

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 fair value of each stock option grant is estimated using a Black-Scholes option-pricing model on the date of grant as follows:

	Years Ended December 31,
	2019			2018
Estimated dividend yield		0.00	%		0.00	%
Weighted-average expected stock price volatility		68.25	%		68.44	%
Weighted-average risk-free interest rate		1.98	%		2.95	%
Expected term of options (in years)		6.61			6.01
Weighted-average fair value per option	$	7.62		$	7.37

The expected volatility rates are estimated based on the actual volatility of comparable public companies over the expected term. The expected term 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 utilizes a weighted value considering actual history and estimated expected term based on the midpoint of final vest date and expiration date. 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 years ended December 31, 2019 and December 31, 2018:

	Outstanding Option Shares			Weighted- Average Exercise Price
Balance as of January 1, 2018		5,416,025		$	0.62
Granted		3,160,097			11.66
Exercised		(220,308	)		0.78
Forfeited/canceled		(592,350	)		2.01
Balance as of December 31, 2018		7,763,464			5.00
Granted		2,647,236			11.64
Exercised		(940,940	)		1.34
Forfeited/canceled		(550,644	)		10.47
Balance as of December 31, 2019		8,919,116			7.02

The intrinsic value of stock options exercised was $10.6 million and $2.7 million during the years ended December 31, 2019 and December 31, 2018, respectively.

There was approximately $29.0 million of total unrecognized compensation cost related to unvested stock options as of December 31, 2019, which is expected to be recognized over a weighted-average period of 2.9 years.

The following table summarizes certain information about stock options granted under the stock option plans which are vested or expected to vest as of December 31, 2019 and December 31, 2018.

Years Ended December 31,		Number of Options		Weighted- Average Remaining Contractual Life (in years)		Weighted- Average Exercise Price
2019	Expected to be exercisable		8,919,116		7.19	$	7.02
2019	Currently exercisable		4,082,663		5.08	$	3.12
2018	Expected to be exercisable		7,763,464		7.50	$	5.00
2018	Currently exercisable		3,418,993		5.37	$	0.76

The following table summarizes certain information about stock options outstanding under the stock option plans for the years ending December 31, 2019 and December 31, 2018, respectively:

Year Ended December 31, 2019
Exercise price	Number of Options Outstanding		Weighted- Average Remaining Life		Number of Options Exercisable
$0.01 - $0.04		1,385,203		1.50		1,385,203
$0.41 - $1.20		2,310,993		6.32		1,721,811
$7.74 - $9.46		1,266,454		9.44		131,644
$10.17 - $13.80		3,891,922		8.96		844,005
$14.91 - $16.00		64,544		9.59		—
		8,919,116				4,082,663

Year Ended December 31, 2018
Exercise price		Number of Options Outstanding		Weighted- Average Remaining Life		Number of Options Exercisable
$0.01 - $0.04			1,397,203		2.49		1,397,203
$	0.41		1,440,920		6.65		1,166,591
$1.18 - $1.20			1,846,255		8.24		748,922
$	8.99		291,023		9.30		33,376
$	10.17		289,408		9.56		5,708
$	11.98		2,070,029		9.78		67,193
$	13.20		428,626		9.93		—
			7,763,464				3,418,993

Retirement Plan

12 Months Ended

Dec. 31, 2019

Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]

Retirement Plan

NOTE 6:

RETIREMENT PLAN

In January 2011, the Company established a defined contribution 401(k) retirement savings plan (the “Retirement Plan”) to all full-time employees. Employee contributions to the Retirement Plan can be 100% of annual compensation up to the prescribed annual maximum under the Internal Revenue Code. Administrative fees of less than $0.1 million were paid by the Company for the years ended December 31, 2019 and December 31, 2018.

The Retirement Plan includes a safe-harbor matching employer contribution equal to 100% of participants’ deferral contributions up to 4%. The Company made contributions of $0.6 million and $0.4 million to the Retirement Plan during the years ended December 31, 2019 and December 31, 2018, respectively.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2019

Commitments And Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

NOTE 7:

COMMITMENTS AND CONTINGENCIES

Litigation

The Company is subject to various legal matters and claims in the ordinary course of business. Although the results of legal proceedings and claims cannot be predicted with certainty, in the opinion of management, there are currently no such known matters that will have a material effect on the consolidated financial condition, results of operations or cash flows of the Company.

Leases

The Company leases office and laboratory space under long-term operating leases. These leases provide tenant improvement allowances and rent abatements as incentives for the Company to either enter into the initial lease agreement or expand within existing premises already under lease and represent all of the Company’s lease obligations as of December 31, 2019. These leases include the following:

•

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.

•

Laboratory and office space at 3054 Cornwallis Road Durham, North Carolina. The property is leased through April 2026 with the option to extend.

•

Laboratory space at 20 TW Alexander Drive, Research Triangle Park, North Carolina. In December 2019, the Company expanded the amount of spaced leased at this site and extended to lease to August 2027.

The following is a schedule of future minimum lease payments for all leases as of December 31, 2019 (in thousands):

	Operating Leases
2020		2,706
2021		3,099
2022		3,196
2023		3,288
2024		2,611
2025 and beyond		3,066
Total		17,966

Supply Agreements

The Company enters into contracts in the normal course of business with CMOs for the manufacture of clinical trial materials and 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 consolidated financial condition, results of operations, or cash flows of the Company.

Net Loss Per Share

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Net Loss Per Share

NOTE 8:

NET LOSS PER SHARE

The Company’s potential dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same.

The Company excluded the following potential shares of common stock from the computation of diluted net loss per share attributable to common stockholders because including them would have had an anti-dilutive effect:

	Years Ended December 31,
	2019		2018
Series A preferred stock (as converted to common stock)		—		12,015,814
Series B preferred stock (as converted to common stock)		—		10,285,376
Outstanding share-based compensation awards converted to common stock		4,032,359		4,796,377
Total		4,032,359		27,097,567

Debt

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Debt

NOTE 9:

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 notes payable (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 consolidated statements of operations until the 2019 Notes were 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 year ended December 31, 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. If the Revolving Line is terminated prior to the maturity date, the Company is required to pay an early termination fee equal to 1.0% of the Revolving Line.

The Company granted Pacific Western Bank a security interest in substantially all of its assets, excluding any of the intellectual property now or hereafter owned, but including any rights to payment from the sale or licensing of any such intellectual property. The Company is prohibited from paying cash dividends without the prior written consent of Pacific Western Bank. The Pacific Western Loan Agreement includes customary representations, warranties and covenants (affirmative and negative) and was amended in December 2019 to allow the Company to maintain a bank account with a non-affiliated bank in the United Kingdom provided that the account balance does not exceed 1.5 million GBP or its U.S. dollar equivalent at any time.

There were no borrowings, and the Company was in compliance with its financial covenants, under the Pacific Western Loan Agreement as of December 31, 2019.

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

INCOME TAXES

NOTE 10:

INCOME TAXES

The Company recorded no income tax expense due to the operating losses incurred for the years ended December 31, 2019 and December 31, 2018.

Significant components of the Company’s deferred tax assets and deferred tax liabilities are as follows (in thousands):

	Years Ended December 31,
	2019			2018
Noncurrent deferred tax assets:
Net operating loss carryforwards	$	23,358		$	9,185
Contribution carryforwards		34			29
Deferred rent		1,099			449
Deferred revenue		13,172			9,454
Other assets		2,444			573
Tax credits		9,090			3,632
Less: valuation allowance		(47,734	)		(22,736	)
Total deferred tax assets, noncurrent		1,463			586

Noncurrent deferred tax liability:
Property and equipment		1,463			586
Total deferred tax liabilities, noncurrent		1,463			586
Net deferred tax assets	$	—		$	—

As of December 31, 2019 and December 31, 2018, the Company has provided a valuation allowance for the full amount of the net deferred tax assets as the realization of the net deferred tax assets is not determined to be more likely than not. The net increase in the valuation allowance for the year ended December 31, 2019 of $25.0 million is comprised of an increase in deferred tax assets, primarily related to deferred revenue and net operating loss carryforwards, for the year.

The reasons for the difference between actual income tax benefit for the years ended December 31, 2019 and December 31, 2018 and the amount computed by applying the statutory federal income tax rate to losses before income tax benefit are as follows (in thousands):

	Year Ended December 31, 2019						Year Ended December 31, 2018
	Amount			% of Pre-Tax Earnings			Amount			% of Pre-Tax Earnings
Income tax expense at statutory rate	$	(19,505	)		21.0	%	$	(9,668	)		21.0	%
State income taxes, net of federal tax benefit		(1,827	)		2.0	%		(909	)		2.0	%
Non-deductible expenses		1,784			(1.9	%)		270			(0.6	%)
R&D and orphan drug credits		(4,810	)		5.1	%		(1,934	)		4.2	%
Other		(639	)		0.7	%		(31	)		0.1	%
Change in valuation allowance		24,997			(26.9	%)		12,272			(26.7	%)
Income tax (benefit) expense	$	—			—		$	—			—

As of December 31, 2019, the Company had federal, state, and foreign net operating loss (“NOL”) carryforwards of approximately $101.3 million, $101.7 million, and $0.4 million respectively. At December 31, 2018, the Company had federal and state NOL carryforwards of approximately $40 million and $39.8 million, respectively. Federal NOL carryforwards of $19.7 million begin to expire in 2030 while the remaining federal NOL carryforward of $81.6 million carries forward indefinitely. The state NOL carryforwards begin to expire in 2025. The foreign NOLs carryforward indefinitely. At December 31, 2019, the Company had federal and state research and development (“R&D”) tax credits of $7.2 million and an amount less than $0.1 million, which begin to expire in 2027 and 2030, respectively. At December 31, 2018, the Company had federal and state tax R&D credits of $3.6 million and an amount less than $0.1 million which begin to expire in 2027 and 2030, respectively. At December 31, 2019 and December 31, 2018, the Company had federal Orphan Drug credits of $1.8 million and $0.7 million, respectively, which begin to expire in 2038. At December 31, 2019 and December 31, 2018, the Company had federal contribution carryforwards of $0.1 million and an amount less than $0.1 million, respectively, which begin to expire in 2020.

The Company incorporated a subsidiary in Australia in 2018. However, the subsidiary has had minimal losses since inception. As such, there are no undistributed earnings as of December 31, 2019. The Company incorporated a subsidiary in the United Kingdom in 2019. However, the subsidiary has had minimal activity since inception. As such, there are no undistributed earnings as of December 31, 2019.

The Company’s ability to utilize its NOL and R&D credit carryforwards may be substantially limited due to ownership changes that may have occurred or that could occur in the future, as required by Section 382 of the Internal Revenue Code of 1986, as amended (the Code), as well as similar state provisions. These ownership changes may limit the amount of NOL and R&D credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an “ownership change,” as defined by Section 382 of the Code, results from a transaction or series of transactions over a three-year period resulting in an ownership change of more than 50 percent of the outstanding stock of a company by certain stockholders or public groups. The Company has not completed a study to assess whether one or more ownership changes have occurred since the Company became a loss corporation under the definition of Section 382. If the Company has experienced an ownership change, utilization of the NOL or R&D credit carryforwards would be subject to an annual limitation, which is determined by first multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term, tax-exempt rate, and then could be subject to additional adjustments, as required. Any such limitation may result in the expiration of a portion of the NOL or R&D credit carryforwards before utilization. Until a study is completed and any limitation known, no amounts are being considered as an uncertain tax position or disclosed as an unrecognized tax benefit. Any carryforwards that expire prior to utilization as a result of such limitations will be removed from deferred tax assets with a corresponding reduction of the valuation allowance. Due to the existence of the valuation allowance, it is not expected that any possible limitation will have an impact on the results of operations of the Company.

The Company reflects in the accompanying consolidated financial statements the benefit of positions taken in a previously filed tax return or expected to be taken in a future tax return only if it is considered ‘more-likely-than-not’ that the position taken will be sustained by the appropriate taxing authority. As of December 31, 2019 and December 31, 2018, the Company had no unrecognized income tax benefits. The Company’s policy for recording interest and penalties relating to uncertain income tax positions is to record them as a component of income tax expense in the accompanying consolidated statements of operations. As of December 31, 2019 and December 31, 2018, the Company had no such accruals.

The Tax Cuts and Jobs Act of 2017 subjects a U.S. shareholder to tax on global intangible low-taxed income (“GILTI”) earned by certain foreign subsidiaries. The FASB Staff Q&A, Topic 740, No. 5, Accounting for Global Intangible Low-Taxed Income, states that an entity can make an accounting policy election to either recognized deferred taxes for temporary basis differences expected to reverse as GILTI in future years or to provide for the tax expense related to GILTI in the year the tax is incurred as a period expense only. The Company has elected to account for GILTI in the year the tax is incurred. The Company does not have a GILTI inclusion in years ends December 31, 2019 or December 31, 2018 and therefore, no GILTI tax has been recorded for the years then ended.

Fair Value Measurements

12 Months Ended

Dec. 31, 2019

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]

FAIR VALUE MEASUREMENTS

NOTE 11:

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 December 31, 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):

December 31, 2019	Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	3,395	$	3,395	$	—	$	—
Repurchase agreements		173,000		—		173,000		—
	$	176,395	$	3,395	$	173,000	$	—

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 Agreements

12 Months Ended

Dec. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

COLLABORATION AND LICENSE AGREEMENTS

NOTE 12:

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 predecessor entities to Servier. 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. 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 actual time of R&D activities performed relative to expected time to be incurred in the future to satisfy the performance obligation. Management evaluates and adjusts the total expected research effort for the performance obligation on a quarterly basis based upon actual research accomplishments and the probability of continuing research efforts in the future. 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 remaining performance obligation associated with the $105.0 million upfront payment is expected to be satisfied over a four year period as of December 31, 2019.

During the years ended December 31, 2019 and December 31, 2018, the Company recognized revenue under the agreement with Servier of approximately $7.3 million and $5.8 million, respectively. Deferred revenue related to the agreement with Servier amounted to $80.9 million and $88.6 million as of December 31, 2019 and December 31, 2018, respectively, of which $15.0 million and $5.8 million, respectively is included in current liabilities. No development or sales-based milestone payments were received during the year ended December 31, 2019 and December 31, 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 years ended December 31, 2019 and December 31, 2018, the Company recognized revenue under the agreement with Gilead of approximately $13.3 million and $3.7 million, respectively. Deferred revenue related to the agreement with Gilead amounted to $1.5 million and $2.3 million as of December 31, 2019 and December 31, 2018, respectively, all of which is included in current liabilities. No development or sales-based milestone payments were received during the year ended December 31, 2019.

Research, Collaboration and License Agreement with the Trustees of the University of Pennsylvania

On January 1, 2018, the Company entered into a Research, Collaboration and License Agreement with the University of Pennsylvania (“Penn”) to collaborate on the preclinical development for gene editing products involving the delivery of an ARCUS nuclease. The Company will provide semi-annual research funding payments of up to $5.0 million for a three-year term to fund the cost of research programs as specified in a mutually agreed-upon research budget and be responsible for post-IND enabling study development activities. The research funding payments will be expensed as incurred; however, if payments made by the Company exceed the costs incurred by Penn in the six-month period, the excess amount will be credited to the Company in the next semi-annual period.

In addition to the research funding payments, if the Company elects to use certain Penn technology, the Company will be required to make development and sales milestone payments totaling up to $16.1 million per product in any one year, assuming the maximum development and sales milestones are met in any one year. An additional $12.3 million per product in sales milestone payments could be payable in other years if other sales thresholds are achieved, thus totaling $28.4 million in aggregate milestone payments per product. Low single-digit royalty percentages are also payable on net sales of certain products.

Penn provided the Company a non-exclusive license for patent rights and know-how to be used in exchange for an upfront payment of $0.3 million. Once the Company has paid $15.0 million in research funding, it then has the option to pay a $1.0 million option fee to obtain a license for additional patent rights.

In October 2019, both parties agreed to adjust the activities conducted under the agreement to focus exclusively on the collaboration’s program to edit the PCSK9 gene to reduce levels of LDL-C in the blood, commonly known as “bad cholesterol”. The agreement’s termination provisions allow the Company to terminate the agreement by providing written notice at least 60 days prior to the due date of the next semi-annual research funding payment. In this event, the Company would not make termination payments to Penn other than for non-cancelable costs and reasonable wind-down costs.

Segment Reporting

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

SEGMENT REPORTING

NOTE 13:

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 year ended December 31, 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 in Durham, 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 year ended December 31, 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

	Years Ended December 31,
(in thousands)	2019			2018
Revenue:
Therapeutics	$	20,632		$	9,523
Food		1,606			1,360
Total segment revenue		22,238			10,883
Segment operational cash expenditures:
Therapeutics	$	45,941		$	35,045
Food		6,984			9,125
Total segment operational cash expenditures		52,925			44,170
Allocation of centralized research and development operational cash expenditures:
Therapeutics	$	24,118		$	11,605
Food		—			2,901
Total allocation of centralized research and development operational cash expenditures		24,118			14,506
Segment operating loss:
Therapeutics	$	(49,427	)	$	(37,127	)
Food		(5,378	)		(10,666	)
Total segment operating loss		(54,805	)		(47,793	)
Adjustments to reconcile segment operating loss to consolidated loss from operations:
Corporate general and administrative cash expenditures	$	(32,569	)	$	(15,892	)
Interest income received		(4,267	)		(1,875	)
Depreciation and amortization		(5,317	)		(2,354	)
Share-based compensation		(8,940	)		(2,453	)
Loss on disposal of assets		(22	)		(14	)
Adjustments to reconcile cash expenditures to GAAP expenses		18,716			22,469
Total consolidated loss from operations	$	(87,204	)	$	(47,912	)

Description of Business and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Description of Business

Use of Estimates

Basis of Presentation

Reclassifications

Cash and Cash Equivalents

Concentrations of Credit Risk

Deferred Equity Offering Costs

Property, Equipment and Software

The depreciation and amortization periods for the Company’s significant property, equipment and software categories are as follows:



Computer hardware and software	3 years
Lab equipment	5 to 7 years
Furniture and office equipment	3 to 5 years
Leasehold improvements	Lesser of remaining lease term or useful life

Repairs and maintenance are charged to operations as incurred, and expenditures for additions and improvements that extend the useful life of the asset are capitalized.

Intangible Assets

Impairment of Long-Lived Assets

Revenue Recognition for Contracts with Customers

The Company’s revenues are generated primarily through collaborative research, license, development and commercialization agreements.

For additional discussion of accounting for collaboration revenues, see Note 12, “Collaboration and license agreements.”

Research and Development

Common Stock Valuation

Comprehensive Loss

Net Loss Per Share

Share-Based Compensation

Income Taxes

Accounting Standards Updates

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 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	)

	Impact of ASC 606 Adoption on Consolidated Balance Sheet as of December 31, 2019
(in thousands)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Deferred revenue - current liabilities	$	16,486		$	(8,017	)	$	8,469
Deferred revenue - noncurrent liabilities		65,895			11,427			77,322
Accumulated deficit		(177,067	)		(3,410	)		(180,477	)

	Impact of ASC 606 Adoption on Consolidated Statement of Operations for the Years Ended December 31, 2019
(in thousands, except per share data)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Revenue	$	22,238		$	(2,413	)	$	19,825
Net loss		(92,877	)		(2,413	)		(95,290	)
Net loss per share - basic and diluted		(2.21	)		(0.06	)		(2.27	)

	Impact of ASC 606 Adoption on Consolidated Statement of Cash Flows for the Years Ended December 31, 2019
(in thousands)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Net loss	$	(92,877	)	$	(2,413	)	$	(95,290	)
Changes in deferred revenue		(7,866	)		2,413			(5,453	)

Description of Business and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Schedule of Depreciation and Amortization Periods for Property, Equipment and Software

The depreciation and amortization periods for the Company’s significant property, equipment and software categories are as follows:



Computer hardware and software	3 years
Lab equipment	5 to 7 years
Furniture and office equipment	3 to 5 years
Leasehold improvements	Lesser of remaining lease term or useful life

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 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	)

	Impact of ASC 606 Adoption on Consolidated Balance Sheet as of December 31, 2019
(in thousands)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Deferred revenue - current liabilities	$	16,486		$	(8,017	)	$	8,469
Deferred revenue - noncurrent liabilities		65,895			11,427			77,322
Accumulated deficit		(177,067	)		(3,410	)		(180,477	)

	Impact of ASC 606 Adoption on Consolidated Statement of Operations for the Years Ended December 31, 2019
(in thousands, except per share data)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Revenue	$	22,238		$	(2,413	)	$	19,825
Net loss		(92,877	)		(2,413	)		(95,290	)
Net loss per share - basic and diluted		(2.21	)		(0.06	)		(2.27	)

	Impact of ASC 606 Adoption on Consolidated Statement of Cash Flows for the Years Ended December 31, 2019
(in thousands)	As reported under ASC 606			Adjustments			Balances without adoption of ASC 606
Net loss	$	(92,877	)	$	(2,413	)	$	(95,290	)
Changes in deferred revenue		(7,866	)		2,413			(5,453	)

Property, Equipment and Software (Tables)

12 Months Ended

Dec. 31, 2019

Property Plant And Equipment [Abstract]

Schedule of Property, Equipment and Software

Property, equipment and software consisted of the following as of December 31 (in thousands):

	2019		2018
Construction in progress	$	697	$	8,600
Leasehold improvements		25,969		5,733
Software		328		278
Laboratory equipment		19,251		10,057
Office equipment		1,602		839
Furniture and fixtures		2,373		1,124
Total property, equipment and software		50,220		26,631
Less accumulated depreciation and amortization		10,649		5,484
Property, equipment and software - net	$	39,571	$	21,147

Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2019

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets, Net

Intangible assets, net, consisted of the following as of December 31 (in thousands):

	2019			2018
License cost	$	1,831		$	1,831
Less: accumulated amortization		(281	)		(247	)
Less: impairments		(118	)		(118	)
Intangible assets, net		1,432			1,466

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 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):

	Years Ended December 31,
	2019		2018
Employee	$	8,354	$	2,431
Nonemployee		586		22
	$	8,940	$	2,453

Schedule of Stock-Based Compensation Expense

Share-based compensation expense related to stock options is included in the following line items in the consolidated statements of operations (in thousands):

	Years Ended December 31,
	2019		2018
Research and development	$	5,639	$	1,817
General and administrative		3,301		636
	$	8,940	$	2,453

Schedule of Stock Options Valuation Assumptions Using a Black-Scholes Option Pricing Model

The fair value of each stock option grant is estimated using a Black-Scholes option-pricing model on the date of grant as follows:

	Years Ended December 31,
	2019			2018
Estimated dividend yield		0.00	%		0.00	%
Weighted-average expected stock price volatility		68.25	%		68.44	%
Weighted-average risk-free interest rate		1.98	%		2.95	%
Expected term of options (in years)		6.61			6.01
Weighted-average fair value per option	$	7.62		$	7.37

Summary of Activity of Option Plans

The following table summarizes activity in the Company’s stock option plans for the years ended December 31, 2019 and December 31, 2018:

	Outstanding Option Shares			Weighted- Average Exercise Price
Balance as of January 1, 2018		5,416,025		$	0.62
Granted		3,160,097			11.66
Exercised		(220,308	)		0.78
Forfeited/canceled		(592,350	)		2.01
Balance as of December 31, 2018		7,763,464			5.00
Granted		2,647,236			11.64
Exercised		(940,940	)		1.34
Forfeited/canceled		(550,644	)		10.47
Balance as of December 31, 2019		8,919,116			7.02

Summary of Stock Options Granted under the Stock Option Plans are Vested or Expected to Vest

The following table summarizes certain information about stock options granted under the stock option plans which are vested or expected to vest as of December 31, 2019 and December 31, 2018.

Years Ended December 31,		Number of Options		Weighted- Average Remaining Contractual Life (in years)		Weighted- Average Exercise Price
2019	Expected to be exercisable		8,919,116		7.19	$	7.02
2019	Currently exercisable		4,082,663		5.08	$	3.12
2018	Expected to be exercisable		7,763,464		7.50	$	5.00
2018	Currently exercisable		3,418,993		5.37	$	0.76

Summary of Stock Options Outstanding under the Stock Option Plans

The following table summarizes certain information about stock options outstanding under the stock option plans for the years ending December 31, 2019 and December 31, 2018, respectively:

Year Ended December 31, 2019
Exercise price	Number of Options Outstanding		Weighted- Average Remaining Life		Number of Options Exercisable
$0.01 - $0.04		1,385,203		1.50		1,385,203
$0.41 - $1.20		2,310,993		6.32		1,721,811
$7.74 - $9.46		1,266,454		9.44		131,644
$10.17 - $13.80		3,891,922		8.96		844,005
$14.91 - $16.00		64,544		9.59		—
		8,919,116				4,082,663

Year Ended December 31, 2018
Exercise price		Number of Options Outstanding		Weighted- Average Remaining Life		Number of Options Exercisable
$0.01 - $0.04			1,397,203		2.49		1,397,203
$	0.41		1,440,920		6.65		1,166,591
$1.18 - $1.20			1,846,255		8.24		748,922
$	8.99		291,023		9.30		33,376
$	10.17		289,408		9.56		5,708
$	11.98		2,070,029		9.78		67,193
$	13.20		428,626		9.93		—
			7,763,464				3,418,993

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 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 December 31, 2019 (in thousands):

	Operating Leases
2020		2,706
2021		3,099
2022		3,196
2023		3,288
2024		2,611
2025 and beyond		3,066
Total		17,966

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share

	Years Ended December 31,
	2019		2018
Series A preferred stock (as converted to common stock)		—		12,015,814
Series B preferred stock (as converted to common stock)		—		10,285,376
Outstanding share-based compensation awards converted to common stock		4,032,359		4,796,377
Total		4,032,359		27,097,567

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Schedule of Deferred Tax Assets and Liabilities

Significant components of the Company’s deferred tax assets and deferred tax liabilities are as follows (in thousands):

	Years Ended December 31,
	2019			2018
Noncurrent deferred tax assets:
Net operating loss carryforwards	$	23,358		$	9,185
Contribution carryforwards		34			29
Deferred rent		1,099			449
Deferred revenue		13,172			9,454
Other assets		2,444			573
Tax credits		9,090			3,632
Less: valuation allowance		(47,734	)		(22,736	)
Total deferred tax assets, noncurrent		1,463			586

Noncurrent deferred tax liability:
Property and equipment		1,463			586
Total deferred tax liabilities, noncurrent		1,463			586
Net deferred tax assets	$	—		$	—

Reconciliation of Federal Statutory Income Tax Rate and Income Tax Benefit

	Year Ended December 31, 2019						Year Ended December 31, 2018
	Amount			% of Pre-Tax Earnings			Amount			% of Pre-Tax Earnings
Income tax expense at statutory rate	$	(19,505	)		21.0	%	$	(9,668	)		21.0	%
State income taxes, net of federal tax benefit		(1,827	)		2.0	%		(909	)		2.0	%
Non-deductible expenses		1,784			(1.9	%)		270			(0.6	%)
R&D and orphan drug credits		(4,810	)		5.1	%		(1,934	)		4.2	%
Other		(639	)		0.7	%		(31	)		0.1	%
Change in valuation allowance		24,997			(26.9	%)		12,272			(26.7	%)
Income tax (benefit) expense	$	—			—		$	—			—

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 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):

December 31, 2019	Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	3,395	$	3,395	$	—	$	—
Repurchase agreements		173,000		—		173,000		—
	$	176,395	$	3,395	$	173,000	$	—

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	$	—

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Segment Reporting (Tables)

12 Months Ended

Dec. 31, 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

	Years Ended December 31,
(in thousands)	2019			2018
Revenue:
Therapeutics	$	20,632		$	9,523
Food		1,606			1,360
Total segment revenue		22,238			10,883
Segment operational cash expenditures:
Therapeutics	$	45,941		$	35,045
Food		6,984			9,125
Total segment operational cash expenditures		52,925			44,170
Allocation of centralized research and development operational cash expenditures:
Therapeutics	$	24,118		$	11,605
Food		—			2,901
Total allocation of centralized research and development operational cash expenditures		24,118			14,506
Segment operating loss:
Therapeutics	$	(49,427	)	$	(37,127	)
Food		(5,378	)		(10,666	)
Total segment operating loss		(54,805	)		(47,793	)
Adjustments to reconcile segment operating loss to consolidated loss from operations:
Corporate general and administrative cash expenditures	$	(32,569	)	$	(15,892	)
Interest income received		(4,267	)		(1,875	)
Depreciation and amortization		(5,317	)		(2,354	)
Share-based compensation		(8,940	)		(2,453	)
Loss on disposal of assets		(22	)		(14	)
Adjustments to reconcile cash expenditures to GAAP expenses		18,716			22,469
Total consolidated loss from operations	$	(87,204	)	$	(47,912	)

Description of Business and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Apr. 01, 2019	Mar. 15, 2019	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Date of incorporation			Jan. 26, 2006
issuance costs			$ 2,622	$ 2,136
Stockholders' equity, reverse stock split		1-for-2.134686
Preferred stock, shares outstanding			0
Net income loss			$ 92,877	46,037
Retained earnings accumulated deficit			177,067	85,187	$ 84,190
Revenue recognition for changes in total estimated time to be incurred in the future to satisfy the performance obligation			$ (1,400)
Tax benefits recognized,likelihood upon ultimate settlement			The tax benefits recognized in the consolidated financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement.
Annual gross revenues			$ 1,070,000
Issued nonconvertible debt			1,000,000
Market value of common stock not held by non-affiliates			700,000
Transition adjustment to opening balance of accumulated deficit			(177,067)	$ (85,187)	(84,190)
Revenue recorded included in deferred revenue			9,400
ASU 2014-09 \| Adjustments
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Net income loss			2,413
Retained earnings accumulated deficit			3,410		997
Transition adjustment to opening balance of accumulated deficit			$ (3,410)		$ (997)
Development Member
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue			60.00%	34.00%
Deferred Revenue			2.00%
Licensing Agreements
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue			33.00%	53.00%
Deferred Revenue			98.00%
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	$ 16.00
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		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. 04, 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 Summary of Significant Accounting Policies - Schedule of Depreciation and Amortization Periods of Property, Equipment and Software (Details)	12 Months Ended
	Dec. 31, 2019
Computer Software Intangible Asset
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Property plant and equipment useful life	3 years
Lab equipment \| Minimum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Property plant and equipment useful life	5 years
Lab equipment \| Maximum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Property plant and equipment useful life	7 years
Furniture and office equipment \| Minimum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Property plant and equipment useful life	3 years
Furniture and office equipment \| Maximum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Property plant and equipment useful life	5 years
Leasehold improvements
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Leasehold improvements	Lesser of remaining lease term or useful life

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	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue - current liabilities	$ 16,486	$ 8,029
Deferred revenue - noncurrent liabilities	65,895	82,217
Accumulated deficit	(177,067)	(84,190)	$ (85,187)
ASU 2014-09 \| Adjustments
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue - current liabilities	(8,017)	407
Deferred revenue - noncurrent liabilities	11,427	590
Accumulated deficit	(3,410)	(997)
ASU 2014-09 \| Balances without adoption of ASC 606
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue - current liabilities	8,469	8,436
Deferred revenue - noncurrent liabilities	77,322	82,807
Accumulated deficit	$ (180,477)	$ (85,187)

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	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 22,238	$ 10,883
Net loss	$ (92,877)	$ (46,037)
Net loss per share attributable to common stockholders- basic and diluted	$ (2.21)	$ (2.92)
ASU 2014-09 \| Adjustments
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ (2,413)
Net loss	$ (2,413)
Net loss per share attributable to common stockholders- basic and diluted	$ (0.06)
ASU 2014-09 \| Balances without adoption of ASC 606
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 19,825
Net loss	$ (95,290)
Net loss per share attributable to common stockholders- basic and diluted	$ (2.27)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

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	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	$ (92,877)	$ (46,037)
Changes in deferred revenue	(7,866)	$ (3,177)
ASU 2014-09 \| Adjustments
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	(2,413)
Changes in deferred revenue	2,413
ASU 2014-09 \| Balances without adoption of ASC 606
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	(95,290)
Changes in deferred revenue	$ (5,453)

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

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-Name Accounting Standards Codification
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+ Details

Property, Equipment and Software - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total property, equipment and software	$ 50,220	$ 26,631
Less accumulated depreciation and amortization	10,649	5,484
Property, equipment and software - net	39,571	21,147
Construction in Progress
Property Plant And Equipment [Line Items]
Total property, equipment and software	697	8,600
Leasehold improvements
Property Plant And Equipment [Line Items]
Total property, equipment and software	25,969	5,733
Software
Property Plant And Equipment [Line Items]
Total property, equipment and software	328	278
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total property, equipment and software	19,251	10,057
Office Equipment
Property Plant And Equipment [Line Items]
Total property, equipment and software	1,602	839
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property, equipment and software	$ 2,373	$ 1,124

Property, Equipment and Software - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 5,317	$ 2,354
Leased Facilities in Durham
Property Plant And Equipment [Line Items]
Construction in progress		8,600
Leasehold improvements	4,400
MCAT \| North Carolina
Property Plant And Equipment [Line Items]
Construction in progress	2,500
Property, Equipment, Leasehold Improvements and Software
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 5,300	$ 2,300

Intangible Assets - Schedule of Intangible Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
License cost	$ 1,831	$ 1,831
Less: accumulated amortization	(281)	(247)
Less: impairments	(118)	(118)
Intangible assets, net	$ 1,432	$ 1,466

Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018
Amortization of intangible assets		$ 0.1	$ 0.1
Payment of non- refundable license fees	$ 1.4
Amortization expense 2020		0.1
Amortization expense 2021		0.1
Amortization expense 2022		0.1
Amortization expense 2023		0.1
Amortization expense 2024		0.1
Amortization expense 2025 and beyond		$ 0.9
Minimum
Amortization period of intellectual property rights		216 months
Maximum
Amortization period of intellectual property rights		257 months

Stockholders' Equity - Additional Information (Details) - $ / shares		12 Months Ended
	Apr. 01, 2019	Dec. 31, 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
Common stock, par value	$ 0.000005	$ 0.000005
Preferred stock, shares authorized	10,000,000	10,000,000	0
Preferred stock, par value	$ 0.0001	$ 0.0001
Common Stock
Stockholders' Equity [Line Items]
Common stock issued upon conversion of convertible preferred stock or convertible notes payable		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 notes payable	2,921,461	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 notes payable	22,301,190

Share-Based Compensation - Additional Information (Details) - USD ($) $ in Millions			12 Months Ended
	Dec. 31, 2019	Mar. 12, 2019	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020	May 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Apr. 30, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding	8,919,116		8,919,116	7,763,464			5,416,025
Stock options outstanding			2,647,236	3,160,097
Common stock, shares issued	51,965,708		51,965,708	16,717,117
Intrinsic value of Stock options exercised	$ 10.6		$ 10.6	$ 2.7
Unrecognized compensation cost	$ 29.0		$ 29.0
Weighted-average period for recognition of compensation cost			2 years 10 months 24 days
2006 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining shares available to be granted								0
Options outstanding	1,385,203		1,385,203
2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding	5,462,954		5,462,954
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%
Stock options outstanding	2,070,959
2019 Plan \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance					2,046,209
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	Mar. 01, 2020	Oct. 21, 2019
Offering period end date	Aug. 31, 2020	Feb. 29, 2020
Common stock, shares issued		44,197
2019 ESPP \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance					511,552

Share-Based Compensation - Schedule of Employee and Nonemployee Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 8,940	$ 2,453
Employee
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	8,354	2,431
Nonemployee
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 586	$ 22

Share-Based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 8,940	$ 2,453
Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	8,940	2,453
Research and Development \| Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	5,639	1,817
General and Administrative \| Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 3,301	$ 636

Share-Based Compensation - Schedule of Stock Options Valuation Assumptions Using a Black-Scholes Option Pricing Model (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Estimated dividend yield	0.00%	0.00%
Weighted-average expected stock price volatility	68.25%	68.44%
Weighted-average risk-free interest rate	1.98%	2.95%
Expected term of options (in years)	6 years 7 months 9 days	6 years 3 days
Weighted-average fair value per option	$ 7.62	$ 7.37

Share-Based Compensation - Summary of Activity of Option Plans (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding Option Shares, Beginning Balance	7,763,464	5,416,025
Stock options outstanding	2,647,236	3,160,097
Option, Exercised	(940,940)	(220,308)
Option, Forfeited/canceled	(550,644)	(592,350)
Outstanding Option Shares, Ending Balance	8,919,116	7,763,464
Weighted-Average Exercise Price Outstanding at Beginning Balance	$ 5.00	$ 0.62
Weighted-Average Exercise Price, Granted	11.64	11.66
Weighted-Average Exercise Price, Exercised	1.34	0.78
Weighted-Average Exercise Price, Forfeited/canceled	10.47	2.01
Weighted-Average Exercise Price Outstanding at Ending Balance	$ 7.02	$ 5.00

Share-Based Compensation - Summary of Stock Options Granted under the Stock Option Plans are Vested or Expected to Vest (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected to be exercisable, Number of Options	8,919,116	7,763,464
Currently exercisable, Number of Options	4,082,663	3,418,993
Expected to be exercisable, Weighted- Average Remaining Contractual Life (in years)	7 years 2 months 8 days	7 years 6 months
Currently exercisable, Weighted- Average Remaining Contractual Life (in years)	5 years 29 days	5 years 4 months 13 days
Expected to be exercisable, Weighted- Average Exercise Price	$ 7.02	$ 5.00
Currently exercisable, Weighted- Average Exercise Price	$ 3.12	$ 0.76

Share-Based Compensation - Summary of Stock Option Outstanding under the Stock Option Plans (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Number of Options Outstanding	8,919,116	7,763,464
Number of Options Exercisable	4,082,663	3,418,993
Exercise price	$ 3.12	$ 0.76
$0.01 - $0.04
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise price, lower limit	0.01	0.01
Exercise price, upper limit	$ 0.04	$ 0.04
Number of Options Outstanding	1,385,203	1,397,203
Weighted- Average Remaining Life	1 year 6 months	2 years 5 months 26 days
Number of Options Exercisable	1,385,203	1,397,203
$0.41 - $1.20
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise price, lower limit	$ 0.41
Exercise price, upper limit	$ 1.20
Number of Options Outstanding	2,310,993
Weighted- Average Remaining Life	6 years 3 months 25 days
Number of Options Exercisable	1,721,811
$7.74 - $9.46
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise price, lower limit	$ 7.74
Exercise price, upper limit	$ 9.46
Number of Options Outstanding	1,266,454
Weighted- Average Remaining Life	9 years 5 months 8 days
Number of Options Exercisable	131,644
$10.17 - $13.80
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise price, lower limit	$ 10.17
Exercise price, upper limit	$ 13.80
Number of Options Outstanding	3,891,922
Weighted- Average Remaining Life	8 years 11 months 15 days
Number of Options Exercisable	844,005
$14.91 - $16.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise price, lower limit	$ 14.91
Exercise price, upper limit	$ 16.00
Number of Options Outstanding	64,544
Weighted- Average Remaining Life	9 years 7 months 2 days
$ 0.41
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Number of Options Outstanding		1,440,920
Weighted- Average Remaining Life		6 years 7 months 24 days
Number of Options Exercisable		1,166,591
Exercise price		$ 0.41
$1.18 - $1.20
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise price, lower limit		1.18
Exercise price, upper limit		$ 1.20
Number of Options Outstanding		1,846,255
Weighted- Average Remaining Life		8 years 2 months 26 days
Number of Options Exercisable		748,922
$ 8.99
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Number of Options Outstanding		291,023
Weighted- Average Remaining Life		9 years 3 months 18 days
Number of Options Exercisable		33,376
Exercise price		$ 8.99
$ 10.17
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Number of Options Outstanding		289,408
Weighted- Average Remaining Life		9 years 6 months 21 days
Number of Options Exercisable		5,708
Exercise price		$ 10.17
$ 11.98
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Number of Options Outstanding		2,070,029
Weighted- Average Remaining Life		9 years 9 months 10 days
Number of Options Exercisable		67,193
Exercise price		$ 11.98
$ 13.20
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Number of Options Outstanding		428,626
Weighted- Average Remaining Life		9 years 11 months 4 days
Exercise price		$ 13.20

Retirement Plan - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2011	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	100.00%
Defined contribution plan, Administrative fees		$ 0.1	$ 0.1
Defined contribution plan, Employer matching contribution percentage of match	100.00%
Defined Contribution Plan, Company made contribution to the retirement plan		$ 0.6	$ 0.4
Maximum
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, Employer matching contribution, percent of employees' gross pay		4.00%

Commitments and Contingencies - Schedule of Future Lease Payments (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2020	$ 2,706
2021	3,099
2022	3,196
2023	3,288
2024	2,611
2025 and beyond	3,066
Total	$ 17,966

Commitments and Contingencies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019
Maximum
Commitments And Contingencies [Line Items]
Agreement termination notice period	1 year

Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Anti-dilutive securities excluded from computation of earnings per share	4,032,359	27,097,567
Series A Convertible Preferred Stock
Anti-dilutive securities excluded from computation of earnings per share		12,015,814
Series B Convertible Preferred Stock
Anti-dilutive securities excluded from computation of earnings per share		10,285,376
Outstanding Share Based Compensation Awards Converted to Common Stock
Anti-dilutive securities excluded from computation of earnings per share	4,032,359	4,796,377

Debt - Additional Information (Details) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Apr. 01, 2019 USD ($) shares	May 31, 2019 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2019 GBP (£)	Mar. 31, 2019 USD ($)
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%
Amount to maintain with non-affiliated bank \| £				£ 1,500,000
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 \| shares			2,921,461
Convertible Notes Payable (2019 Notes)
Debt Instrument [Line Items]
Aggregate principal amount					$ 39,600
Notes accrued interest rate			6.00%	6.00%
Settlement price equal on IPO price per Share			85.00%
Settlement Price Per Share \| $ / shares			$ 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 \| shares	2,921,461		2,921,461

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Noncurrent deferred tax assets:
Net operating loss carryforwards	$ 23,358	$ 9,185
Contribution carryforwards	34	29
Deferred rent	1,099	449
Deferred revenue	13,172	9,454
Other assets	2,444	573
Tax credits	9,090	3,632
Less: valuation allowance	(47,734)	(22,736)
Total deferred tax assets, noncurrent	1,463	586
Noncurrent deferred tax liability:
Property and equipment	1,463	586
Total deferred tax liabilities, noncurrent	$ 1,463	$ 586

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Line Items]
Increase (decrease) in valuation allowance of net deferred tax assets	$ 25,000,000
Net Operating loss carry forwards expiration year	2025
Undistributed earnings	$ 0
Ownership percentage change in outstanding common stock period	3 years
Ownership percentage in outstanding common stock	50.00%
Uncertain tax position	$ 0
Unrecognized tax benefits	0
Unrecognized tax benefits, income tax penalties and interest accrued	0	$ 0
GILTI tax expense	0	0
Federal
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	101,300,000	40,000,000
Net operating loss carryforwards, subject to expiration	$ 19,700,000
Net operating loss carry forward subject to expiration begin year	2030
Net operating loss carryforwards not subject to expiration	$ 81,600,000
Federal contribution carryforwards		$ 100,000
Federal contribution expiration beginning year	2020	2020
Federal \| Maximum
Income Tax Disclosure [Line Items]
Federal contribution carryforwards	$ 100,000
Federal \| Research and Development
Income Tax Disclosure [Line Items]
Tax credit carryforwards	$ 7,200,000	$ 3,600,000
Tax credit carry forwards expiration beginning year	2027	2027
Federal \| Orphan Drug Tax Credit Carry forward
Income Tax Disclosure [Line Items]
Tax credit carryforwards	$ 1,800,000	$ 700,000
Tax credit carry forwards expiration beginning year	2038
State
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 101,700,000	$ 39,800,000
State \| Research and Development
Income Tax Disclosure [Line Items]
Tax credit carry forwards expiration beginning year	2030	2030
State \| Research and Development \| Maximum
Income Tax Disclosure [Line Items]
Tax credit carryforwards	$ 100,000	$ 100,000
Foreign
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 400,000

Income Taxes - Reconciliation of Federal Statutory Income Tax Rate and Income Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of income taxes amount, Amount
Income tax expense at statutory rate, Amount	$ (19,505)	$ (9,668)
State income taxes, net of federal tax benefit, Amount	(1,827)	(909)
Non-deductible expenses, Amount	1,784	270
R&D and orphan drug credits, Amount	(4,810)	(1,934)
Other, Amount	(639)	(31)
Change in valuation allowance, Amount	$ 24,997	$ 12,272
Reconciliation of income taxes rate, Percentage
Income tax expense at statutory rate, Percentage	21.00%	21.00%
State income taxes, net of federal tax benefit, Percentage	2.00%	2.00%
Non-deductible expenses, Percentage	(1.90%)	(0.60%)
R&D and orphan drug credits, Percentage	5.10%	4.20%
Other, Percentage	0.70%	0.10%
Change in valuation allowance, Percentage	(26.90%)	(26.70%)

Fair Value Measurements - Schedule of Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	$ 176,395	$ 95,281
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	3,395	781
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	173,000	94,500
Repurchase Agreements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	173,000	94,500
Repurchase Agreements \| Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	173,000	94,500
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	3,395	781
Money Market Funds \| Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	$ 3,395	$ 781

Collaboration and License Agreements - Additional Information (Details) - USD ($)			1 Months Ended	12 Months Ended
	Sep. 10, 2018	Feb. 24, 2016	Jan. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Collaboration and License Agreements [Line items]
Revenue recorded included in deferred revenue				$ 9,400,000
Deferred revenue				16,486,000	$ 8,436,000
Revenue				22,238,000	10,883,000
Development and Commercial License Agreement \| Servier
Collaboration and License Agreements [Line items]
Upfront payment		$ 105,000,000
Revenue recorded included in deferred revenue				7,300,000	5,800,000
Deferred revenue related to agreement				80,900,000	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				15,000,000	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]
Deferred revenue				1,500,000	2,300,000
Development or sales-based milestone payments				$ 0
Research funding payment term	3 years			3 years
Revenue				$ 13,300,000	$ 3,700,000
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
Semi-annual research funding payments	$ 40,000,000
Research, Collaboration and License Agreement \| University of Pennsylvania
Collaboration and License Agreements [Line items]
Upfront payment			$ 300,000
Aggregate milestone payments			$ 28,400,000
Research funding payment term			3 years
Development or sales-based milestone payments			$ 12,300,000
Payments to collaborator for research funding			15,000,000
Option to pay license fee for additional patent rights			1,000,000
Research, Collaboration and License Agreement \| University of Pennsylvania \| Maximum
Collaboration and License Agreements [Line items]
Semi-annual research funding payments			5,000,000
Development or sales-based milestone payments			$ 16,100,000

Collaboration and License Agreements - Additional Information (Details 1 ) - Servier - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01 $ in Millions	Feb. 24, 2016 USD ($)
Collaboration and License Agreements [Line items]
Revenue from upfront payment	$ 105.0
Estimated period performance obligation	4 years

Segment Reporting - Additional Information (Details)	12 Months Ended
Segment Reporting - Additional Information (Details)	Dec. 31, 2019 Segment
Segment Reporting [Abstract]
Number of reportable segments	2

Segment Reporting - Financial Information with Respect to Company's Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenue	$ 22,238	$ 10,883
Total allocation of centralized research and development operational cash expenditures	82,416	45,122
Loss from operations	(87,204)	(47,912)
Adjustments to reconcile segment operating loss to consolidated loss from operations:
Interest income received	(4,267)	(1,875)
Depreciation and amortization	(5,317)	(2,354)
Share-based compensation	(8,940)	(2,453)
Loss on disposal of assets	(22)	(14)
Adjustments to reconcile cash expenditures to GAAP expenses	18,716	22,469
Operating Segments
Segment Reporting Information [Line Items]
Revenue	22,238	10,883
Total segment operational cash expenditures	52,925	44,170
Total allocation of centralized research and development operational cash expenditures	24,118	14,506
Loss from operations	(54,805)	(47,793)
Operating Segments \| Therapeutics
Segment Reporting Information [Line Items]
Revenue	20,632	9,523
Total segment operational cash expenditures	45,941	35,045
Total allocation of centralized research and development operational cash expenditures	24,118	11,605
Loss from operations	(49,427)	(37,127)
Operating Segments \| Food
Segment Reporting Information [Line Items]
Revenue	1,606	1,360
Total segment operational cash expenditures	6,984	9,125
Total allocation of centralized research and development operational cash expenditures		2,901
Loss from operations	(5,378)	(10,666)
Segment Reconciling Items
Adjustments to reconcile segment operating loss to consolidated loss from operations:
Corporate general and administrative cash expenditures	(32,569)	(15,892)
Interest income received	(4,267)	(1,875)
Depreciation and amortization	(5,317)	(2,354)
Share-based compensation	$ (8,940)	$ (2,453)