Turning Point Therapeutics (TPTX) 10-Q12 Nov 202020 Q3 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2020	Nov. 06, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	TPTX
Entity Registrant Name	Turning Point Therapeutics, Inc.
Entity Central Index Key	0001595893
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		48,172,447
Entity File Number	001-38871
Entity Tax Identification Number	46-3826166
Entity Address, Address Line One	10628 Science Center Drive
Entity Address, Address Line Two	Ste. 200
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	926-5251
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 312,278	$ 48,188
Marketable securities	399,110	360,963
Prepaid and other current assets	6,775	5,796
Total current assets	718,163	414,947
Property and equipment, net	2,551	2,689
Right-of-use lease assets	3,651	4,493
Other assets	268	73
Total assets	724,633	422,202
Current liabilities:
Accounts payable	4,552	2,150
Accrued expenses and other current liabilities	8,542	3,910
Accrued compensation	5,807	6,736
Current portion of operating lease liabilities	1,355	1,236
Total current liabilities	20,256	14,032
Operating lease liabilities, long-term	2,789	3,819
Commitments and contingencies (Note 8)
Stockholders' equity:
Preferred stock, $0.0001 par value;10,000,000 shares authorized at September 30, 2020 and December 31, 2019, zero shares outstanding at September 30, 2020 and December 31, 2019
Common stock, $0.0001 par value; 200,000,000 shares authorized at September 30, 2020 and December 31, 2019; 42,213,364 and 35,915,119 shares issued and outstanding at September 30, 2020 and December 31, 2019, respectively	5	4
Additional paid-in capital	933,971	526,960
Accumulated other comprehensive income	412	271
Accumulated deficit	(232,800)	(122,884)
Total stockholders' equity	701,588	404,351
Total liabilities and stockholders’ equity	$ 724,633	$ 422,202

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	42,213,364	35,915,119
Common stock, shares outstanding	42,213,364	35,915,119

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue	$ 25,000		$ 25,000
Operating expenses:
Research and development	32,213	$ 16,640	79,136	$ 40,802
General and administrative	11,326	5,500	59,761	13,857
Total operating expenses	43,539	22,140	138,897	54,659
Loss from operations	(18,539)	(22,140)	(113,897)	(54,659)
Other income, net	834	1,657	3,981	3,487
Net loss	(17,705)	(20,483)	(109,916)	(51,172)
Unrealized (loss) gain on marketable securities, net of tax	(606)	(24)	141	322
Comprehensive loss	$ (18,311)	$ (20,507)	$ (109,775)	$ (50,850)
Net loss per share, basic and diluted	$ (0.42)	$ (0.63)	$ (2.82)	$ (2.54)
Weighted-average common shares outstanding, basic and diluted	42,185,824	32,312,814	38,914,789	20,178,979

Condensed Statements of Convert

Condensed Statements of Convertible Preferred Stock and Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2018	$ (48,406)		$ 1	$ 2,346		$ (50,753)
Balance, shares at Dec. 31, 2018		65,423,901
Balance at Dec. 31, 2018		$ 145,916
Balance, Shares at Dec. 31, 2018			3,411,516
Option exercises	22			22
Option exercises, Shares			12,337
Stock-based compensation expense	1,926			1,926
Net loss	(13,547)					(13,547)
Balance at Mar. 31, 2019	(60,005)		$ 1	4,294		(64,300)
Balance, Shares at Mar. 31, 2019		65,423,901
Balance at Mar. 31, 2019		$ 145,916
Balance, Shares at Mar. 31, 2019			3,423,853
Balance at Dec. 31, 2018	(48,406)		$ 1	2,346		(50,753)
Balance, shares at Dec. 31, 2018		65,423,901
Balance at Dec. 31, 2018		$ 145,916
Balance, Shares at Dec. 31, 2018			3,411,516
Net loss	(51,172)
Balance at Sep. 30, 2019	420,524		$ 4	522,123	$ 322	(101,925)
Balance, Shares at Sep. 30, 2019			35,839,196
Balance at Mar. 31, 2019	(60,005)		$ 1	4,294		(64,300)
Balance, shares at Mar. 31, 2019		65,423,901
Balance at Mar. 31, 2019		$ 145,916
Balance, Shares at Mar. 31, 2019			3,423,853
Option exercises	591			591
Option exercises, Shares			242,876
Issuance of common stock in connection with a public offering, net of underwriting discounts, commissions, and offering costs	175,151		$ 1	175,150
Issuance of common stock in connection with a public offering, net of underwriting discounts, commissions, and offering costs, Shares			10,637,500
Conversion of preferred stock into common stock	145,916	$ (145,916)	$ 2	145,914
Conversion of convertible preferred stock into common stock, Shares		(65,423,901)	16,993,194
Stock-based compensation expense	3,059			3,059
Net loss	(17,142)					(17,142)
Other comprehensive income (loss)	345				345
Balance at Jun. 30, 2019	247,915		$ 4	329,008	345	(81,442)
Balance, Shares at Jun. 30, 2019			31,297,423
Option exercises	96			96
Option exercises, Shares			41,773
Issuance of common stock in connection with a public offering, net of underwriting discounts, commissions, and offering costs	189,526			189,526
Issuance of common stock in connection with a public offering, net of underwriting discounts, commissions, and offering costs, Shares			4,500,000
Stock-based compensation expense	3,493			3,493
Net loss	(20,483)					(20,483)
Other comprehensive income (loss)	(23)				(23)
Balance at Sep. 30, 2019	420,524		$ 4	522,123	322	(101,925)
Balance, Shares at Sep. 30, 2019			35,839,196
Balance at Dec. 31, 2019	$ 404,351		$ 4	526,960	271	(122,884)
Balance, Shares at Dec. 31, 2019	35,915,119		35,915,119
Option exercises	$ 25			25
Option exercises, Shares			7,129
Stock-based compensation expense	38,365			38,365
Net loss	(60,718)					(60,718)
Other comprehensive income (loss)	(316)				(316)
Balance at Mar. 31, 2020	381,707		$ 4	565,350	(45)	(183,602)
Balance, Shares at Mar. 31, 2020			35,922,248
Balance at Dec. 31, 2019	$ 404,351		$ 4	526,960	271	(122,884)
Balance, Shares at Dec. 31, 2019	35,915,119		35,915,119
Option exercises, Shares	54,653
Net loss	$ (109,916)
Balance at Sep. 30, 2020	$ 701,588		$ 5	933,971	412	(232,800)
Balance, Shares at Sep. 30, 2020	42,213,364		42,213,364
Balance at Mar. 31, 2020	$ 381,707		$ 4	565,350	(45)	(183,602)
Balance, Shares at Mar. 31, 2020			35,922,248
Option exercises	31			31
Option exercises, Shares			3,049
Shares issued under employee stock purchase plan	504			504
Shares issued under employee stock purchase plan, Shares			14,425
Issuance of common stock in connection with a public offering, net of underwriting discounts, commissions, and offering costs	351,611		$ 1	351,610
Issuance of common stock in connection with a public offering, net of underwriting discounts, commissions, and offering costs, Shares			6,229,167
Stock-based compensation expense	7,404			7,404
Net loss	(31,493)					(31,493)
Other comprehensive income (loss)	1,063				1,063
Balance at Jun. 30, 2020	710,827		$ 5	924,899	1,018	(215,095)
Balance, Shares at Jun. 30, 2020			42,168,889
Option exercises	508			508
Option exercises, Shares			44,475
Stock-based compensation expense	8,564			8,564
Net loss	(17,705)					(17,705)
Other comprehensive income (loss)	(606)				(606)
Balance at Sep. 30, 2020	$ 701,588		$ 5	$ 933,971	$ 412	$ (232,800)
Balance, Shares at Sep. 30, 2020	42,213,364		42,213,364

Condensed Statements Of Cash Fl

Condensed Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
Condensed Statements Of Cash Flows - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Operating activities
Net loss	$ (109,916)	$ (51,172)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	54,333	8,478
Depreciation	647	322
Accretion of premium (discount) on marketable securities	(175)	846
Amortization of right-of-use operating lease asset	1,139	707
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(978)	(4,618)
Accounts payable	2,686	1,196
Accrued expenses and other current liabilities	3,423	(122)
Accrued compensation	(929)	2,370
Net cash used in operating activities	(49,420)	(43,685)
Investing activities
Purchases of marketable securities	(351,167)	(264,909)
Sales and maturities of marketable securities	312,986	14,923
Purchases of property and equipment	(874)	(983)
Net cash used in investing activities	(39,055)	(250,969)
Financing activities
Proceeds from issuance of common stock in initial public offering, net		175,151
Proceeds from issuance of common stock in public offering, net of offering costs	351,611	190,186
Costs paid in connection with financing	(114)
Proceeds from issuance of common stock under equity incentive plans	1,068	709
Net cash provided by financing activities	352,565	366,046
Net increase (decrease) in cash and cash equivalents	264,090	71,392
Cash and cash equivalents at the beginning of period	48,188	101,029
Cash and cash equivalents at the end of period	312,278	172,421
Supplemental disclosure of cash flow information:
Cash paid for income taxes	1	1
Supplemental disclosure of non-cash investing and financing information:
Purchases of property and equipment in accounts payable	108	523
Costs incurred in connection with a public offering included in accounts payable and accrued expenses	$ 81	660
Operating lease liabilities arising from obtaining right-of-use assets		$ 5,554

Formation and Business of the C

Formation and Business of the Company; Basis of Presentation	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Formation and Business of the Company; Basis of Presentation	1. Formation and Business of the Company; Basis of Presentation Organization Turning Point Therapeutics, Inc. (the Company) was organized in 2013 and commenced operations in 2014. The Company is a clinical-stage biopharmaceutical company designing and developing novel small molecule, targeted oncology therapies. The Company’s principal operations are in the United States and the Company operates in one segment, with its headquarters in San Diego, California. The Company’s primary activities since inception have been to build infrastructure, conduct research and development, including clinical trials, perform business and financial planning, and raise capital. Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (SEC). Accordingly, since they are interim statements, the accompanying condensed financial statements do not include all of the information and notes required by GAAP for complete financial statements. The unaudited interim financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The condensed balance sheet at December 31, 2019 has been derived from the audited financial statements at that date, but does not include all information and footnotes required by GAAP for complete financial statements. The operating results presented in these unaudited condensed financial statements are not necessarily indicative of the results that may be expected for any future periods. These unaudited condensed financial statements should be read in conjunction with the audited financial statements and the notes thereto for the year ended December 31, 2019 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC. In the opinion of management, the unaudited condensed financial statements and notes thereto include all adjustments that are of a normal and recurring nature that are necessary for the fair presentation of the Company’s financial position and of the results of operations and cash flows for the periods presented. Liquidity Substantial doubt about an entity’s ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within one year from the financial statement issuance date. The Company determined that there are no conditions or events that raise substantial doubt about its ability to continue as a going concern within one year after the date that the unaudited condensed financial statements for the quarter ended September 30, 2020 are issued. The COVID-19 pandemic continues to rapidly evolve and has already resulted in a significant disruption of global financial markets. The Company’s ability to raise additional capital may be adversely impacted by potential worsening global economic conditions and further disruptions to, and volatility in, the credit and financial markets in the United States and worldwide resulting from the pandemic. If such further disruption occurs, the Company could experience an inability to access additional capital.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 2 of the Notes to Financial Statements included in its Annual Report on Form 10‑K for the year ended December 31, 2019. Revenue The Company recognizes revenue in accordance with Accounting Standards Codification (ASC) Topic 606, Revenue From Contracts With Customers The Company assesses the goods or services promised within each contract and determines those that are performance obligations. 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, they are considered performance obligations. The Company assesses whether each promised good or service is distinct for the purpose of identifying the performance obligations in the contract. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (that is, the good or service is capable of being distinct) and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (that is, the promise to transfer the good or service is distinct within the context of the contract). In assessing whether a promised good or service is distinct, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, an entity is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (SSP) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price 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 in the period of adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. For arrangements with licenses of intellectual property that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty has been allocated has been satisfied. 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 then 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, either at a point in time or over time, and if over time, recognition is based on the use of an output or input method. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent liabilities in the Company’s financial statements and accompanying notes. The most significant estimates in the Company’s financial statements relate to determining the SSP of performance obligations associated with collaboration arrangements, preclinical and clinical study accruals and stock-based compensation costs ough the impact of the COVID-19 pandemic to business and operating results presents additional uncertainty, continues to use the best information available to update its critical accounting estimates. Concentration of Credit Risk Substantially all of the Company’s cash, cash equivalents, and marketable securities are held at two financial institutions. Due to the financial strength of the depository institutions, the Company believes these financial institutions represent minimal credit risk. Cash amounts held at financial institutions are insured by the Federal Deposit Insurance Corporation (FDIC) up to $250,000. At September 30, 2020, cash and cash equivalents and marketable securities totaling $711.1 million are either not subject to FDIC insurance, or exceed the FDIC insured limit. The Company’s cash and cash equivalents and marketable securities are invested in short term, high grade securities, and as a result, the Company believes represent a minimal credit risk. Clinical Trial Costs and Accruals A significant portion of the Company’s clinical trial costs relate to contracts with contract research organizations (CROs). The financial terms of the Company’s CRO contracts 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 clinical trial expenses in the Company’s financial statements by matching those expenses with the period in which services and efforts are expended. As part of the process of preparing the Company’s financial statements, the Company evaluates cost information provided by the Company’s CROs concerning estimated monthly expenses for services rendered and unbilled obligations as the sponsor of the Company’s clinical trials. Accordingly, the Company’s clinical trial accrual is dependent upon the timely and accurate reporting of CROs and other third-party vendors, and the Company’s ability to accurately estimate any unbilled obligations. If the contracted amounts are modified, for instance, as a result of changes in the clinical trial protocol or scope of work to be performed, the Company’s modifies its accruals accordingly on a prospective basis. Revisions in the scope of a contract are charged to expense in the period in which the facts that give rise to the revision become reasonably certain . Net Loss Per Share The Company computes basic loss per share by dividing the net loss available to common stockholders by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss assumes the conversion, exercise or issuance of all potential common stock equivalents, unless the effect of inclusion would be anti-dilutive. For purposes of this calculation, common stock equivalents include the Company’s stock options and restricted stock units. The Company excluded stock options to purchase common stock and restricted stock units from the number of shares used to calculate diluted shares outstanding because the inclusion of these potentially dilutive securities would have been antidilutive. Historical outstanding anti-dilutive securities not included in the diluted net loss per share calculation include the following: September 30, 2020 2019 Common stock options 6,669,220 5,119,383 RSUs 21,500 - Total 6,690,720 5,119,383 Recently Adopted Accounting Standards Updates In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses ASU 2016-13 a material impact to the Company’s financial position, results of operations and cash flows. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement: Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement he Company adopted the new standard beginning January 1, 2020 and the adoption had an immaterial impact to the Company’s financial position, results of operations and cash flows.

Marketable Securities

Marketable Securities	9 Months Ended
Marketable Securities	Sep. 30, 2020
Investments Debt And Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities T he Company invests its excess cash in marketable securities, including debt instruments of financial institutions, corporations with investment grade credit ratings, commercial paper and government agencies. At September 30, 2020, marketable securities consisted of the following (in thousands): Unrealized Maturity in Years Amortized Cost Gains Losses Fair Value US Treasuries 2 years or less 62,307 7 (2 ) 62,312 U.S. Government agency securities 2 years or less 65,322 39 (2 ) 65,359 Corporate debt securities 2 years or less 179,017 375 (36 ) 179,356 Commercial paper Less than 1 92,052 31 - 92,083 Total marketable securities $ 398,698 $ 452 $ (40 ) $ 399,110 At December 31, 2019, marketable securities consisted of the following (in thousands): Unrealized Maturity in Years Amortized Cost Gains Losses Fair Value U.S. Government agency securities 2 years or less $ 90,596 $ 42 $ (20 ) $ 90,618 Corporate debt securities 2 years or less 173,595 178 (21 ) 173,752 Commercial paper Less than 1 96,501 92 - 96,593 Total marketable securities $ 360,692 $ 312 $ (41 ) $ 360,963 The Company segments its portfolio based on the underlying risk profiles of their current securities being held. The Company regularly reviews the securities in an unrealized loss position and evaluates the current expected credit loss by considering factors such as historical experience, market data, issuer-specific factors, current and expected future economic conditions. As of September 30, 2020, the Company did not record an allowance for credit loss related to its investment portfolio.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
Fair Value Measurements	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Fair value should maximize the use of observable inputs and minimize the use of unobservable inputs. The Company determines the fair value of financial assets and liabilities using three levels of inputs as follows: Level 1—Inputs which include quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2—Inputs (other than quoted market prices included in Level 1) that are either directly or indirectly observable, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the instrument’s anticipated life. Level 3—Unobservable inputs for assets or liabilities and include little or no market activity. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The Company’s financial assets subject to fair value measurements on a recurring basis and the level of inputs used for such measurements were as follows (in thousands): Fair Value Measurements at September 30, 2020 Using: Level 1 Level 2 Level 3 Total Money market funds $ 224,358 $ - $ - $ 224,358 U.S. Treasuries 62,312 - - 62,312 U.S. government agency securities - 65,359 - 65,359 Corporate debt securities - 184,363 - 184,363 Commercial paper - 174,069 - 174,069 Total cash equivalents and marketable securities $ 286,670 $ 423,791 $ - $ 710,461 Fair Value Measurements at December 31, 2019 Using: Level 1 Level 2 Level 3 Total Money market funds $ 45,085 $ - $ - $ 45,085 U.S. government agency securities - 90,618 - 90,618 Corporate debt securities - 173,752 - 173,752 Commercial paper - 96,593 - 96,593 Total cash equivalents and marketable securities $ 45,085 $ 360,963 $ - $ 406,048

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
Property and Equipment, Net	Sep. 30, 2020
Property Plant And Equipment [Abstract]
Property and Equipment, Net	5. Property and Equipment, Net Property and equipment, net consisted of the following (in thousands) September 30, December 31, 2020 2019 Laboratory equipment $ 1,347 $ 885 Computer equipment and software 956 910 Tenant improvements 1,108 1,108 Furniture and fixtures 357 357 Property and equipment 3,768 3,260 Less: accumulated depreciation (1,217 ) (571 ) Property and equipment, net $ 2,551 $ 2,689 Depreciation expense for the three months ended September 30, 2020 and 2019 was $0.2 million and $0.1 million, respectively. Depreciation expense for the nine months ended September 30, 2020 and 2019 was $0.6 million and $0.3 million, respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
Accrued Expenses and Other Current Liabilities	Sep. 30, 2020
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following (in thousands) September 30, December 31, 2020 2019 Accrued research and development expenses $ 7,740 $ 3,414 Accrued general and administrative expenses 777 451 Other current liabilities 25 45 Total $ 8,542 $ 3,910

Zai License Agreement

Zai License Agreement	9 Months Ended
Zai License Agreement	Sep. 30, 2020
Research And Development [Abstract]
Zai License Agreement	7. Zai License Agreement Terms of Agreement On July 6, 2020, the Company entered into a License Agreement (the Zai License Agreement) with Zai Lab (Shanghai) Co., Ltd. (Zai), pursuant to which the Company grants Zai exclusive rights to develop and commercialize products containing the Company’s drug candidate, repotrectinib (the Products), in Mainland China, Hong Kong, Macau and Taiwan (each, a region and collectively, the Territory). The Company retains exclusive rights to, among other things, develop, manufacture and commercialize the Products outside the Territory. The Company will supply or have supplied to Zai the Products for use in the Territory pursuant to a supply agreement for agreed upon consideration, except that Zai has the right, at its election, to package and label the Products in or outside the Territory for use in the Territory Pursuant to the terms of the Zai License Agreement, the Company has received an upfront cash payment of $25.0 million and will be eligible to receive up to $151.0 million in development and sales milestone payments, consisting of up to $46.0 million of development milestones and up to $105.0 million of sales milestones. In addition, during the term of the Zai License Agreement, Zai will be obligated to pay the Company tiered percentage royalties ranging from teens on annual net sales of the Products in the Territory, subject to adjustments in specified circumstances Zai will be responsible for conducting the development and commercialization activities in the Territory related to the Products at Zai’s own expense, subject to limited exceptions pursuant to which the Company may be responsible for the cost. The Company will be responsible for global clinical studies of the Products, including the portions that may be conducted in the Territory, at the Company’s expense, except that Zai will participate in global clinical studies of the Products through clinical trial sites in the Territory as agreed as of the effective date of the Zai License Agreement and may, at Zai’s election, participate in future global clinical studies of the Products through clinical trial sites in the Territory, in each case at Zai’s expense. The Zai License Agreement will continue in effect until expiration of the last royalty term for a Product in any region in the Territory, where the royalty term for a Product in a region continues until the later of (i) the date of the last-to-expire valid claim within Company’s patent rights that covers the Product in such region in the Territory; (ii) the expiry of the regulatory exclusivity for such Product in such region; or (iii) the close of business of the day that is exactly 10 years after the date of the first commercial sale of such Product in such region. Subject to the terms of the Zai License Agreement, Zai may terminate the Zai License Agreement for convenience by providing written notice to the Company, which termination will be effective following a prescribed notice period. In addition, the Company may terminate the Zai License Agreement under specified circumstances if Zai or certain other parties challenge the Company’s patent rights. Either party may terminate the Zai License Agreement for the other party’s uncured material breach of the Zai License Agreement, with a customary notice and cure period, for the other party’s insolvency or if the other party is acquired in a change of control transaction and the acquirer is engaged in activities with a competing product that is not divested or discontinued within a specified period. After termination (but not natural expiration), other than certain terminations by Zai for cause, the Company is entitled to retain a worldwide and perpetual license from Zai to exploit the Products. Revenue Recognition The Company determined that two performance obligations existed: (1) the exclusive license, bundled with the associated know-how and (2) the Company's initial obligation to supply repotrectinib for clinical development in the Territory. The total transaction price of $25.7 million was allocated to the performance obligations on the basis of the relative stand-alone selling price estimated for each performance obligation. In estimating the stand-alone selling price for each performance obligation, the Company developed assumptions that require judgment and included forecasted revenues, expected development timelines, discount rates, probabilities of technical and regulatory success and costs for manufacturing clinical supplies. The Company delivered the license and technical know-how to Zai in the third quarter of 2020 to satisfy this performance obligation, and accordingly the Company recognized license revenue of $25.0 million in the third quarter of 2020. The $0.7 million in consideration allocable to the clinical supply performance obligation will be recognized when clinical trial material has been shipped by the Company and Zai obtains control of the goods, upon delivery, over the period of the obligation. As of September 30, 2020, the Company has not recognized any revenue associated with the clinical supply performance obligation. The Company assessed the Zai License Agreement to determine whether a financing component exists and concluded that a significant financing component does not exist. The upfront payment received by the was subject to foreign tax withholdings. The Company recorded this tax expense to general and administrative expense in the Condensed Statements of Operations and Comprehensive Loss.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Operating Leases The Company has one lease agreement for the leasing of office and laboratory space with an initial lease term of four years resulting in an initial lease liability of $4.0 million and a right-of-use asset of $3.7 million, which is net of $0.3 million of the Company’s deferred gain from the office and laboratory space surrendered in the prior year. The right-of-use asset and corresponding lease liability was estimated assuming a remaining lease term of 48 months and an estimated discount rate of 8.5%, which was the Company’s incremental borrowing rate at the date of the lease commencement. Future minimum payments under the lease as of September 30, 2020 are as follows (in thousands) 2020 (Three months remaining) 410 2021 1,668 2022 1,718 2023 872 Total future minimum lease payments 4,668 Less: amounts representing interest (524 ) Total lease liability $ 4,144 Remaining lease term 2.8 years Rent expense was $0.4 million and $0.4 million for the three months ended September 30, 2020 and 2019, respectively. The Company paid $0.4 million and $0.4 million of cash payments related to its operating lease agreement for the three months ended September 30, 2020 and 2019, respectively. Rent expense was $1.1 million and $0.7 million for the nine months ended September 30, 2020 and 2019, respectively. The Company paid $1.2 million and $0.8 million of cash payments related to its operating lease agreement for the nine months ended September 30, 2020 and 2019, respectively.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
Stockholders' Equity	Sep. 30, 2020
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity At the Market Offering In August 2020, the Company entered into an Open Market Sale Agreement with Jefferies LLC, or ATM facility, under which the Company may offer and sell, from time to time, at its sole discretion, up to $250.0 million shares of the Company’s common stock. To date, the Company has not yet sold any shares of common stock under the ATM facility. Stock Option Plan T In addition, the number of shares of common stock available for issuance under the Plan will be automatically increased on the first day of each calendar year during the ten-year term of the Plan, beginning with January 1, 2020 and ending with January 1, 2029, by an amount equal to 4% of the outstanding number of shares of the Company’s common stock on December 31 of the preceding calendar year or such lesser amount as determined by the Company’s board of directors. On January 1, 2020, the Company added 1,436,604 shares to the Plan. At September 30, 2020, the Plan had 2,579,374 total shares available for issuance Options expire within a period of not more than ten years from the date of grant. Initial option grants to employees typically vest 25% after one year and monthly thereafter over a three-year period and expire three months after employee termination. Subsequent option grants to employees and grants to non-employees typically vest monthly over a four-year period. The majority of options outstanding at September 30, 2020 had vesting periods of four years. The weighted-average grant-date fair value of options granted to employees was $44.97 and $32.92 for the three months ended September 30, 2020 and 2019, respectively, and was $41.96 and $20.12, for the nine months ended September 30, 2020 and 2019 , respectively. As of September 30, 2020, there was $98.8 million in total unrecognized compensation expense expected to be recognized over a weighted average period of 2.70 years. The following summarizes option activity under the Plan for the periods presented: Outstanding Options Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Balance as of December 31, 2019 5,254,269 $ 14.59 9.0 $ 250,611 Options granted 1,820,320 $ 61.80 Options exercised (54,653 ) $ 10.31 Options forfeited or cancelled (350,716 ) $ 18.26 Balance as of September 30, 2020 6,669,220 $ 27.32 7.6 $ 400,411 Options vested and exercisable as of September 30, 2020 2,793,909 $ 13.22 5.9 $ 207,141 The fair values of the employee stock options granted during the three and nine months ended September 30, 2020 and 2019 were estimated at the date of grant using the Black-Scholes option-pricing model with the following average assumptions: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Risk-free interest rate 0.40 % 1.64 % 1.27 % 2.18 % Volatility 80.4 % 80.2 % 79.3 % 79.6 % Expected term (in years) 6.08 6.06 6.06 6.05 Dividend yield - - - - Restricted Stock Units The summary of the Company’s restricted stock unit activity for the periods presented is as follows: Number of Restricted Stock Units Outstanding Weighted Average Grant Date Fair Value Balance as of December 31, 2019 - $ - Granted 21,500 $ 59.94 Vested - $ - Forfeited - $ - Outstanding as of September 30, 2020 21,500 $ 59.94 No 2019 Employee Stock Purchase Plan In April 2019, the Company’s board of directors and stockholders approved and adopted the 2019 Employee Stock Purchase Plan (the ESPP). The ESPP became effective immediately prior to the date of the underwriting agreement related to the Company’s initial public offering. The ESPP permits eligible employees who elect to participate in an offering under the ESPP to have up to 15% of their eligible earnings withheld, subject to certain limitations, to purchase shares of common stock pursuant to the ESPP. The price of common stock purchased under the ESPP is equal to 85 percent of the lower of the fair market value of the common stock at the commencement date of each offering period or the relevant date of purchase. Each offering period is 24 months, with new offering periods commencing every six months on the dates of June 11 and December 11 of each year. Each offering period consists of four six month purchase periods (each a Purchase Period) during which payroll deductions of the participants are accumulated under the ESPP. The last business day of each Purchase Period is referred to as the “Purchase .” Purchase Dates are every six months on the dates of June 10 and December 10 of each year. The assumptions used for the nine months ended September 30, 2020 and the resulting estimates of weighted-average fair value per share for stock purchased under the ESPP during such period were as follows Nine Months Ended September 30, 2020 Risk-free interest rate 0.17 - 2.13% Volatility 70.6 - 91.6% Expected term (in years) 0.50 - 2.00 Dividend yield - Departure of Former Chief Scientific Officer (CSO) On January 9, 2020, the Company entered into a Transition Separation and Consulting Agreement (the Transition Agreement) with the Company’s former CSO, Dr. Jingrong Jean Cui. In connection with this Transition Agreement, Dr. Cui resigned from her position as CSO effective January 31, 2020 and thereafter agreed to serve as a consultant to the Company on an as needed basis until June 30, 2020 The Company determined that the modification to extend the term of vested stock options was a Type I modification pursuant to ASC 718, Compensation – Stock Compensation Stock-Based Compensation Expense Stock-based compensation expense for options granted under the Company's equity plans totaled the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Research and development $ 3,912 $ 1,771 $ 10,799 $ 4,052 General and administrative 4,652 1,722 43,534 4,426 Total stock-based compensation $ 8,564 $ 3,493 $ 54,333 $ 8,478 Common Stock Reserved for Future Issuance Common stock reserved for future issuance consisted of the following: September 30, 2020 Common stock options outstanding 6,669,220 Options to purchase common stock available for issuance under the Plan 2,579,374 Shares available for purchase under ESPP 263,879 Total 9,512,473

Subsequent Events

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	10. Subsequent Events October 2020 Public Offering In October 2020, the Company completed a public offering under which it sold 5,287,357 shares of common stock at an offering price of $87.00 per share. The net proceeds from this offering, after deducting underwriting discounts, commissions, and offering costs, were approximately $433.6 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (SEC). Accordingly, since they are interim statements, the accompanying condensed financial statements do not include all of the information and notes required by GAAP for complete financial statements. The unaudited interim financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The condensed balance sheet at December 31, 2019 has been derived from the audited financial statements at that date, but does not include all information and footnotes required by GAAP for complete financial statements. The operating results presented in these unaudited condensed financial statements are not necessarily indicative of the results that may be expected for any future periods. These unaudited condensed financial statements should be read in conjunction with the audited financial statements and the notes thereto for the year ended December 31, 2019 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC. In the opinion of management, the unaudited condensed financial statements and notes thereto include all adjustments that are of a normal and recurring nature that are necessary for the fair presentation of the Company’s financial position and of the results of operations and cash flows for the periods presented.
Revenue	Revenue The Company recognizes revenue in accordance with Accounting Standards Codification (ASC) Topic 606, Revenue From Contracts With Customers The Company assesses the goods or services promised within each contract and determines those that are performance obligations. 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, they are considered performance obligations. The Company assesses whether each promised good or service is distinct for the purpose of identifying the performance obligations in the contract. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (that is, the good or service is capable of being distinct) and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (that is, the promise to transfer the good or service is distinct within the context of the contract). In assessing whether a promised good or service is distinct, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, an entity is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (SSP) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price 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 in the period of adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. For arrangements with licenses of intellectual property that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty has been allocated has been satisfied. 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 then 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, either at a point in time or over time, and if over time, recognition is based on the use of an output or input method.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent liabilities in the Company’s financial statements and accompanying notes. The most significant estimates in the Company’s financial statements relate to determining the SSP of performance obligations associated with collaboration arrangements, preclinical and clinical study accruals and stock-based compensation costs ough the impact of the COVID-19 pandemic to business and operating results presents additional uncertainty, continues to use the best information available to update its critical accounting estimates.
Concentration of Credit Risk	Concentration of Credit Risk Substantially all of the Company’s cash, cash equivalents, and marketable securities are held at two financial institutions. Due to the financial strength of the depository institutions, the Company believes these financial institutions represent minimal credit risk. Cash amounts held at financial institutions are insured by the Federal Deposit Insurance Corporation (FDIC) up to $250,000. At September 30, 2020, cash and cash equivalents and marketable securities totaling $711.1 million are either not subject to FDIC insurance, or exceed the FDIC insured limit. The Company’s cash and cash equivalents and marketable securities are invested in short term, high grade securities, and as a result, the Company believes represent a minimal credit risk.
Clinical Trial Costs and Accruals	Clinical Trial Costs and Accruals A significant portion of the Company’s clinical trial costs relate to contracts with contract research organizations (CROs). The financial terms of the Company’s CRO contracts 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 clinical trial expenses in the Company’s financial statements by matching those expenses with the period in which services and efforts are expended. As part of the process of preparing the Company’s financial statements, the Company evaluates cost information provided by the Company’s CROs concerning estimated monthly expenses for services rendered and unbilled obligations as the sponsor of the Company’s clinical trials. Accordingly, the Company’s clinical trial accrual is dependent upon the timely and accurate reporting of CROs and other third-party vendors, and the Company’s ability to accurately estimate any unbilled obligations. If the contracted amounts are modified, for instance, as a result of changes in the clinical trial protocol or scope of work to be performed, the Company’s modifies its accruals accordingly on a prospective basis. Revisions in the scope of a contract are charged to expense in the period in which the facts that give rise to the revision become reasonably certain .
Net Loss Per Share	Net Loss Per Share The Company computes basic loss per share by dividing the net loss available to common stockholders by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss assumes the conversion, exercise or issuance of all potential common stock equivalents, unless the effect of inclusion would be anti-dilutive. For purposes of this calculation, common stock equivalents include the Company’s stock options and restricted stock units. The Company excluded stock options to purchase common stock and restricted stock units from the number of shares used to calculate diluted shares outstanding because the inclusion of these potentially dilutive securities would have been antidilutive. Historical outstanding anti-dilutive securities not included in the diluted net loss per share calculation include the following: September 30, 2020 2019 Common stock options 6,669,220 5,119,383 RSUs 21,500 - Total 6,690,720 5,119,383
Recently Adopted Accounting Standards Updates	Recently Adopted Accounting Standards Updates In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses ASU 2016-13 a material impact to the Company’s financial position, results of operations and cash flows. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement: Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement he Company adopted the new standard beginning January 1, 2020 and the adoption had an immaterial impact to the Company’s financial position, results of operations and cash flows.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
Summary of Significant Accounting Policies (Tables)	Sep. 30, 2020
Accounting Policies [Abstract]
Schedule of Outstanding Anti-Dilutive Securities not Included Diluted Net Loss Per Share Calculation	Historical outstanding anti-dilutive securities not included in the diluted net loss per share calculation include the following: September 30, 2020 2019 Common stock options 6,669,220 5,119,383 RSUs 21,500 - Total 6,690,720 5,119,383

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
Marketable Securities (Tables)	Sep. 30, 2020
Investments Debt And Equity Securities [Abstract]
Summary of Marketable Securities	At September 30, 2020, marketable securities consisted of the following (in thousands): Unrealized Maturity in Years Amortized Cost Gains Losses Fair Value US Treasuries 2 years or less 62,307 7 (2 ) 62,312 U.S. Government agency securities 2 years or less 65,322 39 (2 ) 65,359 Corporate debt securities 2 years or less 179,017 375 (36 ) 179,356 Commercial paper Less than 1 92,052 31 - 92,083 Total marketable securities $ 398,698 $ 452 $ (40 ) $ 399,110 At December 31, 2019, marketable securities consisted of the following (in thousands): Unrealized Maturity in Years Amortized Cost Gains Losses Fair Value U.S. Government agency securities 2 years or less $ 90,596 $ 42 $ (20 ) $ 90,618 Corporate debt securities 2 years or less 173,595 178 (21 ) 173,752 Commercial paper Less than 1 96,501 92 - 96,593 Total marketable securities $ 360,692 $ 312 $ (41 ) $ 360,963

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Subject to Fair Value Measurements on a Recurring Basis and the Level of Inputs	The Company’s financial assets subject to fair value measurements on a recurring basis and the level of inputs used for such measurements were as follows (in thousands): Fair Value Measurements at September 30, 2020 Using: Level 1 Level 2 Level 3 Total Money market funds $ 224,358 $ - $ - $ 224,358 U.S. Treasuries 62,312 - - 62,312 U.S. government agency securities - 65,359 - 65,359 Corporate debt securities - 184,363 - 184,363 Commercial paper - 174,069 - 174,069 Total cash equivalents and marketable securities $ 286,670 $ 423,791 $ - $ 710,461 Fair Value Measurements at December 31, 2019 Using: Level 1 Level 2 Level 3 Total Money market funds $ 45,085 $ - $ - $ 45,085 U.S. government agency securities - 90,618 - 90,618 Corporate debt securities - 173,752 - 173,752 Commercial paper - 96,593 - 96,593 Total cash equivalents and marketable securities $ 45,085 $ 360,963 $ - $ 406,048

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
Property and Equipment, Net (Tables)	Sep. 30, 2020
Property Plant And Equipment [Abstract]
Summary of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands) September 30, December 31, 2020 2019 Laboratory equipment $ 1,347 $ 885 Computer equipment and software 956 910 Tenant improvements 1,108 1,108 Furniture and fixtures 357 357 Property and equipment 3,768 3,260 Less: accumulated depreciation (1,217 ) (571 ) Property and equipment, net $ 2,551 $ 2,689

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
Accrued Expenses and Other Current Liabilities (Tables)	Sep. 30, 2020
Payables And Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands) September 30, December 31, 2020 2019 Accrued research and development expenses $ 7,740 $ 3,414 Accrued general and administrative expenses 777 451 Other current liabilities 25 45 Total $ 8,542 $ 3,910

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
Commitments and Contingencies (Tables)	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Summary of Operating Leases Future Minimum Payments	Future minimum payments under the lease as of September 30, 2020 are as follows (in thousands) 2020 (Three months remaining) 410 2021 1,668 2022 1,718 2023 872 Total future minimum lease payments 4,668 Less: amounts representing interest (524 ) Total lease liability $ 4,144 Remaining lease term 2.8 years

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
Stockholders' Equity (Tables)	Sep. 30, 2020
Equity [Abstract]
Schedule of Option Activity Under the Plan	The following summarizes option activity under the Plan for the periods presented: Outstanding Options Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Balance as of December 31, 2019 5,254,269 $ 14.59 9.0 $ 250,611 Options granted 1,820,320 $ 61.80 Options exercised (54,653 ) $ 10.31 Options forfeited or cancelled (350,716 ) $ 18.26 Balance as of September 30, 2020 6,669,220 $ 27.32 7.6 $ 400,411 Options vested and exercisable as of September 30, 2020 2,793,909 $ 13.22 5.9 $ 207,141
Schedule of Fair Values of Employee Stock Options Granted	The fair values of the employee stock options granted during the three and nine months ended September 30, 2020 and 2019 were estimated at the date of grant using the Black-Scholes option-pricing model with the following average assumptions: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Risk-free interest rate 0.40 % 1.64 % 1.27 % 2.18 % Volatility 80.4 % 80.2 % 79.3 % 79.6 % Expected term (in years) 6.08 6.06 6.06 6.05 Dividend yield - - - - The assumptions used for the nine months ended September 30, 2020 and the resulting estimates of weighted-average fair value per share for stock purchased under the ESPP during such period were as follows
Summary of Restricted Stock Unit Activity	The summary of the Company’s restricted stock unit activity for the periods presented is as follows: Number of Restricted Stock Units Outstanding Weighted Average Grant Date Fair Value Balance as of December 31, 2019 - $ - Granted 21,500 $ 59.94 Vested - $ - Forfeited - $ - Outstanding as of September 30, 2020 21,500 $ 59.94
Schedule of Stock Based Compensation Expense	Stock-based compensation expense for options granted under the Company's equity plans totaled the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Research and development $ 3,912 $ 1,771 $ 10,799 $ 4,052 General and administrative 4,652 1,722 43,534 4,426 Total stock-based compensation $ 8,564 $ 3,493 $ 54,333 $ 8,478
Schedule of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance consisted of the following: September 30, 2020 Common stock options outstanding 6,669,220 Options to purchase common stock available for issuance under the Plan 2,579,374 Shares available for purchase under ESPP 263,879 Total 9,512,473

Formation and Business of the_2

Formation and Business of the Company; Basis of Presentation - Additional Information (Details)	Oct. 08, 2013Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segments	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	9 Months Ended
	Sep. 30, 2020USD ($)
Significant Accounting Policies [Line Items]
Exceed of federal deposits insurance limit	$ 711,100,000
ASU 2016-13
Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2020
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
ASU 2018-13
Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2020
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
Maximum
Significant Accounting Policies [Line Items]
Cash FDIC insured amount	$ 250,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Outstanding Anti-Dilutive Securities not Included Diluted Net Loss Per Share Calculation (Detail) - shares	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the diluted net loss per share	6,690,720	5,119,383
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the diluted net loss per share	6,669,220	5,119,383
RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the diluted net loss per share	21,500

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Marketable Securities [Line Items]
Amortized Cost	$ 398,698	$ 360,692
Unrealized Gains	452	312
Unrealized Losses	(40)	(41)
Fair Value	$ 399,110	$ 360,963
US Treasuries
Marketable Securities [Line Items]
Maturity in Years	2 years or less
Amortized Cost	$ 62,307
Unrealized Gains	7
Unrealized Losses	(2)
Fair Value	$ 62,312
U.S. Government Agency Securities
Marketable Securities [Line Items]
Maturity in Years	2 years or less	2 years or less
Amortized Cost	$ 65,322	$ 90,596
Unrealized Gains	39	42
Unrealized Losses	(2)	(20)
Fair Value	$ 65,359	$ 90,618
Corporate Debt Securities
Marketable Securities [Line Items]
Maturity in Years	2 years or less	2 years or less
Amortized Cost	$ 179,017	$ 173,595
Unrealized Gains	375	178
Unrealized Losses	(36)	(21)
Fair Value	$ 179,356	$ 173,752
Commercial Paper
Marketable Securities [Line Items]
Maturity in Years	Less than 1	Less than 1
Amortized Cost	$ 92,052	$ 96,501
Unrealized Gains	31	92
Fair Value	$ 92,083	$ 96,593

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets Subject to Fair Value Measurements on a Recurring Basis and the Level of Inputs (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	$ 710,461	$ 406,048
Money Market Funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	224,358	45,085
US Treasuries
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	62,312
U.S Government Agency Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	65,359	90,618
Corporate Debt Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	184,363	173,752
Commercial Paper
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	174,069	96,593
Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	286,670	45,085
Level 1 \| Money Market Funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	224,358	45,085
Level 1 \| US Treasuries
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	62,312
Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	423,791	360,963
Level 2 \| U.S Government Agency Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	65,359	90,618
Level 2 \| Corporate Debt Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	184,363	173,752
Level 2 \| Commercial Paper
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents and market securities	$ 174,069	$ 96,593

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 3,768	$ 3,260
Less: accumulated depreciation	(1,217)	(571)
Property and equipment, net	2,551	2,689
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,347	885
Computer Equipment And Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	956	910
Tenant Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,108	1,108
Furniture And Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 357	$ 357

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Depreciation	$ 200	$ 100	$ 647	$ 322

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued research and development expenses	$ 7,740	$ 3,414
Accrued general and administrative expenses	777	451
Other current liabilities	25	45
Total	$ 8,542	$ 3,910

Zai License Agreement - Additio

Zai License Agreement - Additional Information (Details) - USD ($)	3 Months Ended
	Sep. 30, 2020	Jul. 06, 2020
Research And Development Arrangement Contract To Perform For Others [Line Items]
Total transaction price allocated to performance obligation	$ 25,700,000
License
Research And Development Arrangement Contract To Perform For Others [Line Items]
License revenue recognized	25,000,000
Clinical Supply
Research And Development Arrangement Contract To Perform For Others [Line Items]
Total transaction price allocated to performance obligation	$ 700,000
Zai License Agreement
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront cash payment received		$ 25,000,000
Zai License Agreement \| Maximum
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payments eligible to receive		151,000,000
Zai License Agreement \| Development Milestones \| Maximum
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payments eligible to receive		46,000,000
Zai License Agreement \| Sales Milestones \| Maximum
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payments eligible to receive		$ 105,000,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Thousands	Jul. 01, 2019USD ($)OperatingLease	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
Number of operating lease \| OperatingLease	1
Operating lease, initial lease term	4 years
Operating lease, right-of-use asset	$ 3,700	$ 3,651		$ 3,651		$ 4,493
Operating lease right-to-use liability	$ 4,000	$ 4,144		$ 4,144
Operating lease, remaining lease term	48 months	2 years 9 months 18 days		2 years 9 months 18 days
Operating lease, discount rate	8.50%
Deferred gain	$ 300
Rent expense		$ 400	$ 400	$ 1,100	$ 700
Operating lease, cash payments		$ 400	$ 400	$ 1,200	$ 800

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Operating Leases Future Minimum Payments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jul. 01, 2019
Commitments And Contingencies Disclosure [Abstract]
2020 (Three months remaining)	$ 410
2021	1,668
2022	1,718
2023	872
Total future minimum lease payments	4,668
Less: amounts representing interest	(524)
Operating lease right-to-use liability	$ 4,144	$ 4,000
Remaining lease term	2 years 9 months 18 days	48 months

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Aug. 01, 2020	Jan. 01, 2020	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance			2,579,374				2,579,374
Weighted-average grant-date fair value of options granted to employees			$ 44.97		$ 32.92		$ 41.96	$ 20.12
Unrecognized compensation expense related to unvested options			$ 98,800				$ 98,800
Unrecognized compensation expense, weighted-average period for recognition							2 years 8 months 12 days
Common stock initially reserved for ESPP			9,512,473				9,512,473
Stock-based compensation expense			$ 8,564		$ 3,493		$ 54,333	$ 8,478
General and Administrative Expenses
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			4,652		$ 1,722		$ 43,534	$ 4,426
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense, weighted-average period for recognition							3 years 9 months 10 days
Number of awards vested							0
Unrecognized compensation expense related to unvested awards			$ 1,200				$ 1,200
Chief Scientific Officer \| Transition Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period						18 months
Cash severance expense				$ 1,200
Chief Scientific Officer \| Transition Agreement \| General and Administrative Expenses
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense				$ 31,400
Chief Scientific Officer \| Maximum \| Transition Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Extended options vesting period						12 months
Chief Scientific Officer \| Minimum \| Transition Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Extended options vesting period						90 days
2019 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based award, description							The Company’s 2019 Equity Incentive Plan (the Plan) provides for the grant of stock options, restricted stock and other equity awards of the Company’s common stock to employees, officers, consultants, and directors. In addition, the number of shares of common stock available for issuance under the Plan will be automatically increased on the first day of each calendar year during the ten-year term of the Plan, beginning with January 1, 2020 and ending with January 1, 2029, by an amount equal to 4% of the outstanding number of shares of the Company’s common stock on December 31 of the preceding calendar year or such lesser amount as determined by the Company’s board of directors. On January 1, 2020, the Company added 1,436,604 shares to the Plan. At September 30, 2020, the Plan had 2,579,374 total shares available for issuance
Term of plan							ten-year
Plan expiration date							Jan. 1, 2029
Percentage of outstanding common stock added to plan each year							4.00%
Number of shares added to plan		1,436,604
Number of shares available for issuance			2,579,374				2,579,374
2019 Equity Incentive Plan \| After 2nd year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options expiration period							3 months
2019 Equity Incentive Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options expiration period							10 years
2019 Equity Incentive Plan \| Employees \| After one year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights							Initial option grants to employees typically vest 25% after one year and monthly thereafter over a three-year period and expire three months after employee termination.
Exercise price of options as percentage							25.00%
2019 Equity Incentive Plan \| Employees \| After 2nd year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period							3 years
2019 Equity Incentive Plan \| Employees and non - employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights							Subsequent option grants to employees and grants to non-employees typically vest monthly over a four-year period. The majority of options outstanding at September 30, 2020 had vesting periods of four years.
Options vesting period							4 years
2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of eligible earnings withholding			15.00%				15.00%
Percentage of price of common stock purchased under ESPP							85.00%
Common stock initially reserved for ESPP			288,938				288,938
ATM Facility
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock authorized for issuance yet to issue	$ 250,000

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Option Activity Under the Plan (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares
Outstanding Options
Balance as of December 31, 2019 \| shares	5,254,269
Options granted \| shares	1,820,320
Options exercised \| shares	(54,653)
Options forfeited or cancelled \| shares	(350,716)
Balance as of September 30, 2020 \| shares	6,669,220	5,254,269
Options vested and exercisable as of September 30, 2020 \| shares	2,793,909
Weighted Average Exercise Price Per Share
Balance as of December 31, 2019 \| $ / shares	$ 14.59
Options granted \| $ / shares	61.80
Options exercised \| $ / shares	10.31
Options forfeited or cancelled \| $ / shares	18.26
Balance as of September 30, 2020 \| $ / shares	27.32	$ 14.59
Options vested and exercisable as of September 30, 2020 \| $ / shares	$ 13.22
Weighted average remaining contractual term
Weighted average remaining contractual term	7 years 7 months 6 days	9 years
Options vested and exercisable as of September 30, 2020	5 years 10 months 24 days
Aggregate Value Intrinsic
Balance as of December 31, 2019 \| $	$ 400,411	$ 250,611
Options vested and exercisable as of September 30, 2020 \| $	$ 207,141

Stockholders' Equity - Schedu_2

Stockholders' Equity - Schedule of Fair Values of Employee Stock Options Granted (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	0.40%	1.64%	1.27%	2.18%
Volatility	80.40%	80.20%	79.30%	79.60%
Expected term (in years)	6 years 29 days	6 years 21 days	6 years 21 days	6 years 18 days
2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate. minimum			0.17%
Risk-free interest rate. maximum			2.13%
Volatility, minimum			70.60%
Volatility, maximum			91.60%
Minimum \| 2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)			6 months
Maximum \| 2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)			2 years

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Units	9 Months Ended
	Sep. 30, 2020$ / sharesshares
Number of Restricted Stock Units Outstanding
Granted	21,500
Vested	0
Outstanding as of September 30, 2020	21,500
Weighted Average Grant Date Fair Value
Granted \| $ / shares	$ 59.94
Outstanding as of September 30, 2020 \| $ / shares	$ 59.94

Stockholders' Equity - Schedu_3

Stockholders' Equity - Schedule of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 8,564	$ 3,493	$ 54,333	$ 8,478
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	3,912	1,771	10,799	4,052
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 4,652	$ 1,722	$ 43,534	$ 4,426

Stockholders' Equity - Schedu_4

Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Details) - shares	Sep. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Common stock options outstanding	6,669,220	5,254,269
Options to purchase common stock available for issuance under the Plan	2,579,374
Shares available for purchase under ESPP	263,879
Total	9,512,473

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Subsequent Event - October 2020 Public Offering $ / shares in Units, $ in Millions	1 Months Ended
	Oct. 31, 2020USD ($)$ / sharesshares
Subsequent Event [Line Items]
Number of common stock, shares sold \| shares	5,287,357
Offering price per share \| $ / shares	$ 87
Net proceeds from offering after deducting underwriting discounts, commissions and offering costs \| $	$ 433.6