G1 Therapeutics (GTHX) 10-K 24 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Feb. 22, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	GTHX
Entity Registrant Name	G1 THERAPEUTICS, INC.
Entity Central Index Key	0001560241
Current Fiscal Year End Date	--12-31
Title of 12(b) Security	Common Stock $.0001 par value
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
ICFR Auditor Attestation Flag	true
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	001-38096
Entity Address, Address Line One	700 Park Offices Drive
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Research Triangle Park
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27709
City Area Code	919
Local Phone Number	213-9835
Entity Tax Identification Number	26-3648180
Document Annual Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		41,959,379
Entity Public Float			$ 820.8
Documents Incorporated by Reference	Documents Incorporated by Reference Portions of the Registrant’s Definitive Proxy Statement relating to the Annual Meeting of S tock holders, scheduled to be held on June 1 7 , 20 2 1 , are incorporated by reference into Part III of this r eport. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the Registrant’s fiscal year ended December 31, 2020.

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 207,306	$ 269,208
Restricted cash	63	63
Accounts Receivable	237
Prepaid expenses and other current assets	8,786	1,732
Total current assets	216,392	271,003
Property and equipment, net	2,482	3,538
Restricted cash	437	437
Operating lease assets	8,026	9,853
Other assets	1,215
Total assets	228,552	284,831
Current liabilities
Accounts payable	3,572	3,684
Accrued expenses	16,486	15,403
Deferred revenue	237
Other current liabilities	3,148	682
Total current liabilities	23,443	19,769
Loan payable	19,893
Operating lease liabilities	7,865	9,535
Total liabilities	51,201	29,304
Stockholders’ equity
Common stock, $0.0001 par value, 120,000,000 shares authorized as of December 31, 2020 and December 31, 2019, respectively; 38,140,756 and 37,638,260 shares issued as of December 31, 2020 and December 31, 2019, respectively; 38,114,090 and 37,611,594 shares outstanding as of December 31, 2020 and December 31, 2019, respectively	4	4
Treasury stock, 26,666 shares	(8)	(8)
Additional paid-in capital	613,462	592,384
Accumulated deficit	(436,107)	(336,853)
Total stockholders’ equity	177,351	255,527
Total liabilities and stockholders' equity	$ 228,552	$ 284,831

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares, issued	38,140,756	37,638,260
Common stock, shares, outstanding	38,114,090	37,611,594
Treasury stock, shares	26,666	26,666

Statements of Operations

Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
License revenue	$ 45,285
Revenue, Product and Service [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember
Operating expenses
Research and development	$ 73,271	$ 89,002	$ 70,683
General and administrative	68,490	40,039	18,603
Total operating expenses	141,761	129,041	89,286
Loss from operations	(96,476)	(129,041)	(89,286)
Other income (expense):
Interest income	952	6,579	3,998
Interest expense	(1,778)
Other income (expense)	(542)	15
Total other income (expense), net	(1,368)	6,594	3,998
Loss before income taxes	(97,844)	(122,447)	(85,288)
Income tax expense	1,410
Net loss	$ (99,254)	$ (122,447)	$ (85,288)
Net loss per share, basic and diluted	$ (2.62)	$ (3.27)	$ (2.56)
Weighted average common shares outstanding, basic and diluted	37,878,026	37,499,256	33,316,719

Statements of Redeemable Conver

Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2017	$ 93,388	$ 3	$ (8)	$ 222,511	$ (129,118)
Balance (in shares) at Dec. 31, 2017		28,420,511	(26,666)
Public offering (Follow-on Financings)	303,522	$ 1		303,521
Public offering (Follow-on Financings), shares		7,360,000
Public offering (ATM)	36,068			36,068
Public offering (ATM), shares		752,008
Exercise of common stock options	1,797			1,797
Exercise of common stock options (in shares)		736,273
Stock-based compensation	10,225			10,225
Stock financing costs	(892)			(892)
Net loss during year	(85,288)				(85,288)
Balance at Dec. 31, 2018	358,820	$ 4	$ (8)	573,230	(214,406)
Balance (in shares) at Dec. 31, 2018		37,268,792	(26,666)
Exercise of common stock options	2,705			2,705
Exercise of common stock options (in shares)		369,468
Stock-based compensation	16,449			16,449
Net loss during year	(122,447)				(122,447)
Balance at Dec. 31, 2019	255,527	$ 4	$ (8)	592,384	(336,853)
Balance (in shares) at Dec. 31, 2019		37,638,260	(26,666)
Exercise of common stock options	$ 2,308			2,308
Exercise of common stock options (in shares)	502,496	502,496
Stock-based compensation	$ 18,770			18,770
Net loss during year	(99,254)				(99,254)
Balance at Dec. 31, 2020	$ 177,351	$ 4	$ (8)	$ 613,462	$ (436,107)
Balance (in shares) at Dec. 31, 2020		38,140,756	(26,666)

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities
Net loss	$ (99,254)	$ (122,447)	$ (85,288)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation	18,770	16,449	10,225
Depreciation and amortization	582	356	175
Loss on disposal of fixed assets	322		8
Amortization of debt issuance costs	615
Non-cash interest expense	166
Non-cash equity interest, net	(867)
Change in operating assets and liabilities
Accounts Receivable	(237)
Prepaid expenses and other assets	(5,545)	(219)	113
Accounts payable	(244)	248	(1,002)
Accrued expenses and other liabilities	1,713	6,042	1,446
Deferred revenue	237
Deferred rent			16
Net cash used in operating activities	(83,742)	(99,571)	(74,307)
Cash flows from investing activities
Proceeds from disposal of property and equipment	152
Purchases of property and equipment		(2,716)	(709)
Net cash provided/used in investing activities	152	(2,716)	(709)
Cash flows from financing activities
Proceeds from stock options exercised	2,308	2,705	1,797
Proceeds from loan agreement	20,000
Payments of debt issuance costs	(620)
Proceeds from public offering, net of underwriting fees and commissions			339,589
Payment of public offering costs			(892)
Net cash provided by financing activities	21,688	2,705	340,494
Net change in cash, cash equivalents and restricted cash	(61,902)	(99,582)	265,478
Cash, cash equivalents and restricted cash
Beginning of period	269,708	369,290	103,812
End of period	207,806	269,708	369,290
Supplemental disclosure of cash flow information
Cash paid for interest	997
Non-cash investing and financing activities
Upfront project costs and other current assets in accounts payable and accrued expenses	$ 132	43	107
Purchases of equipment in accounts payable and accrued expenses		41	$ 100
Operating lease liabilities arising from obtaining right-of-use asset		$ 8,947

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	1. Description of Business G1 Therapeutics, Inc. (the “Company”) is a commercial-stage biopharmaceutical company based in Research Triangle Park, North Carolina focused on the development and commercialization of novel small molecule therapeutics for the treatment of patients with cancer. Our first FDA-approved product, COSELA™ (trilaciclib) is the first and only therapy indicated to proactively help protect bone marrow from the damage of chemotherapy and is first innovation in managing myelosuppression in decades. The Company was incorporated on May 19, 2008 in the state of Delaware. The Company is advancing two clinical-stage programs. Our lead compound trilaciclib is a first-in-class therapy designed to help protect against chemotherapy-induced myelosuppression. Trilaciclib helps protect HSPCs in bone marrow by transiently inhibiting CDK4/6 leading to a temporary arrest of susceptible host cells during chemotherapy in ES-SCLC patients. This reduces the duration and severity of neutropenia and other myelosuppressive consequences of chemotherapy. In addition, trilaciclib activates and enhances the immune system response driving increased anti-tumor efficacy, which we continue to explore in clinical trials. We are developing trilaciclib in a variety of tumors, including small cell lung cancer (SCLC), colorectal cancer (CRC), metastatic triple negative breast cancer (mTNBC), neoadjuvant breast cancer, non-small cell lung cancer (NSCLC) and bladder cancer. Trilaciclib, a transient IV CDK4/6 inhibitor, is a novel therapeutic approach which is given before chemotherapy that temporarily blocks progression through the cell cycle. This provides two benefits. First, it proactively helps protect HSPCs in bone marrow leading to preservation of neutrophils, erythrocytes, and platelets (called myeloprotection) which reduces the occurrences and severity of neutropenia and other myelosuppressive consequences of chemotherapy. This myeloprotection benefit has been conclusively proven in double-blind placebo-controlled clinical trials in extensive-stage small cell lung cancer. Second, trilaciclib activates and enhances the immune system response driving increased anti-tumor efficacy, which we are exploring in clinical trials. On February 12, 2021, COSELA (trilaciclib) for injection was approved by the U.S. Food and Drug Administration (FDA) to decrease the incidence of chemotherapy-induced myelosuppression in adult patients when administered prior to a platinum/etoposide-containing regimen or topotecan-containing regimen for extensive stage small cell lung cancer (ES-SCLC). COSELA is expected to be commercially available through G1’s specialty pharmacy partner network in early March. COSELA is administered intravenously as a 30-minute infusion completed within 4 hours prior to the start of chemotherapy and is the first FDA-approved therapy to provide proactive, multilineage protection from chemotherapy-induced myelosuppression. The approval of COSELA is based on data from three randomized, placebo-controlled trials that showed patients receiving COSELA prior to chemotherapy had clinically meaningful and statistically significant reduction in the duration and severity of neutropenia, reduction of red blood cell transfusions, as well as improvements in other myeloprotection measures, compared to patients receiving chemotherapy without COSELA. In June 2020, the Company entered into a three-year co-promotion agreement for COSELA in the United States and Puerto Rico with Boehringer Ingelheim. The agreement is limited to support SCLC. Under the terms of the agreement, the Company will book revenue in the United States and Puerto Rico and retain development and commercialization rights to trilaciclib. The Company will lead marketing, market access and medical engagement initiatives; Boehringer Ingelheim will lead sales force engagements. In addition, discussions with European regulatory authorities have indicated existing data is sufficient to support a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) for trilaciclib for myeloprotection in SCLC, which the Company plans to pursue in collaboration with a partner. In August 2020, the Company entered into an exclusive license agreement with Nanjing Simcere Dongyuan Pharmaceutical Co., Ltd (“Simcere”) for development and commercialization rights for trilaciclib in all indications in Greater China (mainland China, Hong Kong, Macau and Taiwan). Under the terms of the agreement, the Company received an upfront payment of $14.0 million in September 2020 and will be eligible to receive up to $156.0 million in development and commercial milestone payments. Simcere will also pay the Company tiered low double-digit royalties on annual net sales of trilaciclib in Greater China. As part of this agreement, Simcere will participate in global clinical trials of trilaciclib and the companies will be responsible for all development and commercialization costs in their respective territories. We are also executing on our tumor-agnostic strategy to evaluate the potential benefits of trilaciclib to patients with other tumors that are treated with chemotherapy. We have two on-going trials: a pivotal 1L colorectal cancer (CRC) study and a Phase 2 neoadjuvant breast cancer (I-SPY 2). We intend to initiate another pivotal study in mTNBC (including 1L and 2L patients) and have two additional Phase 2 studies: a 2L/3L non-small cell lung cancer (NSCLC) trial in post-checkpoint patients and a 1L bladder cancer trial with chemotherapy and a checkpoint inhibitor. These studies across treatment settings and tumor types will evaluate trilaciclib’s dual benefits in both multi-lineage myeloprotection and anti-tumor efficacy. The Company is developing rintodestrant, an oral SERD, as a monotherapy and in combination with CDK4/6 inhibitors, initially Ibrance® (palbociclib), for the treatment of ER+ breast cancer. In 2018, the Company initiated a Phase 1/2a (dose escalation/dose expansion) clinical trial in ER+, HER2- breast cancer. Preliminary data from the Phase 1 potion of this trial were presented at the 2019 ESMO Congress, showing that rintodestrant was well tolerated and demonstrated evidence of anti-tumor activity in heavily pre-treated patients. The mature monotherapy data were presented at the 2020 San Antonio Breast Cancer Symposium (SABCS) conference, confirming the safety and efficacy results of the preliminary analysis . Based on these findings the Company advanced an 800 mg dose of rintodestrant into a 40-patient Phase 2 combination trial with palbociclib, a CDK4/6 inhibitor. The Company has completed enrollment of patients in this trial, and expects to disclose initial safety and efficacy data in the second quarter of 2021. Palbociclib is being provided under a non-exclusive clinical supply agreement that was signed with Pfizer in February 2020. We will evaluate partnering options for rintodestrant following the data read-out from our combination study. Lerociclib is a differentiated oral CDK4/6 inhibitor being developed for use in combination with other targeted therapies in multiple oncology indications. In 2020, the Company entered into separate, exclusive agreements with EQRx, Inc. (rights for U.S., Europe, Japan and all markets outside Asia-Pacific) and Genor Biopharma Co. Inc. (rights for Asia-Pacific, excluding Japan) for the development and commercialization of lerociclib in all indications. Combined, these agreements provide $26.0 million in upfront payments to the Company, and the opportunity for up to $330.0 million in potential milestone payments, plus sales-based royalties. EQRx, Inc. and Genor Biopharma Co. Inc. are responsible for all costs related to the development and commercialization of lerociclib in their respective territories. The Company’s financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business. As of December 31, 2020, the Company had an accumulated deficit of $436.1 million. The Company has reported a net loss in all fiscal periods since inception and expects to incur substantial losses in the future to conduct research and development and pre-commercialization activities. As of December 31, 2020, the Company had cash and cash equivalents of $207.3 million. The Company expects that its existing cash and cash equivalents will enable it to fund its operating expenses and capital expenditure requirements for greater than 12 months from the date of filing this Annual Report.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	2. Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation The Company has prepared the accompanying financial statements in conformity with generally accepted accounting principles in the United States of America (“U.S. GAAP”). Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and the accompanying notes. Actual results could differ from those estimates. These estimates include the Company’s common stock valuation, stock compensation, and deferred tax asset valuation allowance. Revenue Recognition For elements of those arrangements that we determine should be accounted for under ASC 606, Revenue from Contracts with Customers (“ASC 606”), we assess which activities in our license or collaboration agreements are performance obligations that should be accounted for separately and determine the transaction price of the arrangement, which includes the assessment of the probability of achievement of future milestones and other potential consideration. For arrangements that include multiple performance obligations, such as granting a license or performing manufacturing or research and development activities, we allocate the transaction price based on the relative standalone selling price and recognize revenue that is allocated to the respective performance obligation when (or as) control is transferred to the customer and the performance obligation is satisfied. Accordingly, we develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. These key assumptions may include revenue forecasts, clinical development timelines and costs, discount rates and probabilities of clinical and regulatory success. Licenses of Intellectual Property If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue associated with the bundled performance obligation. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of progress and related revenue recognition. Milestone Payments At the inception of each arrangement that includes developmental and regulatory milestone payments, the Company evaluates whether the achievement of each milestone specifically relates to the Company’s efforts to satisfy a performance obligation or transfer a distinct good or service within a performance obligation. The Company evaluates each milestone to determine when and how much of the milestone to include in the transaction price. The Company first estimates the amount of the milestone payment that the Company could receive using either the expected value or the most likely amount approach. The Company primarily uses the most likely amount approach as that approach is generally most predictive for milestone payments with a binary outcome. Then, the Company considers whether any portion of that estimated amount is subject to the variable consideration constraint (that is, whether it is probable that a significant reversal of cumulative revenue would not occur upon resolution of the uncertainty). The Company updates the estimate of variable consideration included in the transaction price at each reporting date which includes updating the assessment of the likely amount of consideration and the application of the constraint to reflect current facts and circumstances. Royalties For arrangements 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 will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any revenue related to sales-based royalties or milestone payments based on the level of sales. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents at December 31, 2020 and 2019 consist of amounts on deposit in banks, including checking accounts, money market accounts and certificates of deposit. Cash deposits are all in financial institutions in the United States. As part of the lease for the new office space, the Company obtained a standby letter of credit in the amount of $0.5 million related to the security deposit. This letter of credit is secured by money market funds at the financial institution. Therefore, these funds are classified as restricted cash on the balance sheet. The letter of credit will be reduced ratably on each anniversary of the commencement of the lease until the end of the lease term. Concentration of Credit Risk Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents. Deposits with financial institutions are insured, up to certain limits, by the Federal Deposit Insurance Corporation (“FDIC”). The Company’s cash deposits often exceed the FDIC insurance limit; however, all deposits are maintained with high credit quality institutions and the Company has not experienced any losses in such accounts. The financial condition of financial institutions is periodically reassessed, and the Company believes the risk of any loss is minimal. The Company believes the risk of any loss on cash due to credit risk is minimal. Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation is generally calculated using the straight-line method over the following estimated useful lives: Computer equipment 5 years Laboratory equipment 5 years Furniture and fixtures 7 years Leasehold improvements 7 years Costs associated with maintenance and repairs are charged to expense as incurred. Property and equipment held under leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the related asset. Impairment of Long-lived Assets The Company evaluates its long-lived assets for indicators of possible impairment by comparison of the carrying amounts to future net undiscounted cash flows expected to be generated by such assets when events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess carrying value of the asset over the asset’s fair value based on discounted estimates of future cash flows. For the years ended December 31, 2020, 2019 and 2018, the Company’s management evaluated its long-lived assets and determined no impairment charge was needed. Research and Development Research and development expenses consist of costs incurred to further the Company’s research and development activities and include salaries and related employee benefits, manufacturing of pharmaceutical active ingredients and drug products, costs associated with clinical trials, nonclinical activities, regulatory activities, research-related overhead expenses and fees paid to expert consultants, external service providers and contract research organizations which conduct certain research and development activities on behalf of the Company. Costs incurred in the research and development of products are charged to research and development expense as incurred. Each reporting period, management estimated and accrued research and development expenses, including external clinical study costs associated with clinical trial activities. The process of estimating and accruing expenses involved reviewing contracts and purchase orders, identifying services that have been provided on the Company’s behalf, and estimating the level of service performed and the associated cost incurred for the service when the Company has not yet been invoiced or otherwise notified of the actual costs. Costs for clinical trial activities were estimated based on an evaluation of vendors’ progress towards completion of specific tasks, using data such as patient enrollment, clinical site activations or information provided by vendors regarding their actual costs incurred. Payments for these activities are based on the terms of individual contracts and payment timing may differ significantly from the period in which the services were performed. The Company determines accrual estimates through reports from and discussions with applicable personnel and outside service providers as to the progress or state of completion of trials, or the services completed. The estimates of accrued external clinical study costs as of each balance sheet date are based on the facts and circumstances known at the time. Fair value of Financial Instruments The Company provides disclosure of financial assets and financial liabilities that are carried at fair value based on the price that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurements may be classified based on the amount of subjectivity associated with the inputs to fair valuation of these assets and liabilities using the following three levels: Level 1 Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2 Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability and inputs that are derived principally from or corroborated by observable market data by correlation or other means. Level 3 Unobservable inputs that reflect the Company’s estimates of the assumptions that market participants would use in pricing the asset or liability. The Company develops these inputs based on the best information available, including its own data. The carrying amounts of cash, cash equivalents, accounts payable and accrued liabilities approximate fair value because of their short-term nature. At December 31, 2020 and 2019 these financial instruments and respective fair values have been classified as follows (in thousands): Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant other unobservable inputs (Level 3) Balance at December 31, 2020 Assets Money market funds $ 190,180 $ — $ — $ 190,180 Certificates of Deposit 15,970 — — 15,970 Total assets at fair value: $ 206,150 $ — $ — $ 206,150 Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant other unobservable inputs (Level 3) Balance at December 31, 2019 Assets Money market funds $ 252,563 $ — $ — $ 252,563 Certificates of Deposit 15,873 — — 15,873 Total assets at fair value: $ 268,436 $ — $ — $ 268,436 During the twelve months ended December 31, 2020 and December 31, 2019, there were no changes in valuation methodology. The Loan Payable (discussed in Note 7), which is classified as a Level 3 liability, has a variable interest rate and the carrying value approximates its fair value. As of December 31, 2020, the carrying value was $19.9 million. Patent Costs Costs associated with the submission of patent applications are expensed as incurred given the uncertainty of the future economic benefits of the patents. Patent-related legal expenses included in general and administrative costs were approximately $2,761 thousand, $2,114 thousand, and $1,352 thousand for the years ended December 31, 2020, 2019 and 2018, respectively. Income Taxes Income taxes are accounted for using the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statements carrying amounts of assets and liabilities and their respective tax bases, operating loss carryforwards, and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 740, Accounting for Income Taxes Stock-Based Compensation The primary type of stock-based payments utilized by the Company are stock options. The Company accounts for stock-based employee compensation arrangements by measuring the cost of employee services received in exchange for all equity awards granted based on the fair value of the award on the grant date. The fair value of each employee stock option is estimated on the date of grant using an options pricing model. The Company currently uses the Black-Scholes valuation model to estimate the fair value of its share- based payments. The model requires management to make a number of assumptions including expected volatility, expected life, risk-free interest rate and expected dividends. The Company accounts for stock-based non-employee compensation arrangements by recording the expense of such services based on the fair value of the equity instrument as estimated using the Black-Scholes pricing model. The fair value of the equity instrument is charged to operating expense over the term of the service agreement. In accordance with the implementation of ASU No. 2018-07 on January 1, 2019, the fair value of non-employee stock options is no longer be re-measured each reporting period. Segment Information The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. All of the Company’s assets are held in the United States. 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. There was no difference between net loss and comprehensive loss for each of the periods presented in the accompanying financial statements. Leases We determine if an arrangement is a lease at inception. Operating lease assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating leases are included in operating lease assets, other current liabilities, and operating lease liabilities on our balance sheet at December 31, 2020. Operating lease assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date to determine the present value of future payments. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Debt Issuance Costs Debt issuance costs are amortized to interest expense over the estimated life of the related debt based on the effective interest method. In accordance with ASC 835, Interest, we present debt issuance costs on the condensed balance sheet as a direct deduction from the associated debt. Coronavirus (COVID-19) Impact on Operations The Company has implemented business continuity plans to address the COVID-19 pandemic and minimize disruptions to ongoing operations. Enrollment of patients in current and future clinical trials may be impacted by COVID-19. The Company does not anticipate significant supply chain delays or shortages as a result of the COVID-19 pandemic. COVID-19 travel limitations and government-mandated work-from-home or shelter-in-place orders, may reduce the number of in-person meetings with prescribers and fewer patient visits with physicians, potentially resulting in fewer new prescriptions. The established a COVID-19 response team which continually monitors the impact of COVID-19 on its operations. The COVID-19 response team manages workplace protocols that govern employees use of our office. To mitigate the impact of COVID-19 on its business, the Company put in place the following safety measures for its employees, patients, healthcare professionals, and suppliers to limit exposure: the Company substantially restricted travel, supplied personal protective equipment to employees, limited access to its headquarters and asked most of its staff to work remotely. In addition, the Company transitioned most of its employees to working remotely and added bandwidth and VPN capacity to its infrastructure. The Company will continue to monitor the impact of COVID-19 on its operations and report to the Board regularly on the progress of its response to the COVID-19 outbreak. Recent Accounting Pronouncements Adoption of New Accounting Standards In August 2018, the FASB issued ASU No. 2018-15, Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). The FASB issued ASU 2018-15 to align the requirements for capitalizing implementation costs incurred in a cloud-based hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). ASU 2018-15 became effective for annual and interim reporting periods beginning after December 15, 2019. The Company adopted ASU 2018-15 on January 1, 2020 using the prospective method of adoption, and the adoption did not have a material impact to the financial statements.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Property and Equipment	3. Property and Equipment Property and equipment consists of the following (in thousands): December 31, 2020 December 31, 2019 Computer equipment $ 327 $ 332 Laboratory equipment 334 871 Furniture and fixtures 866 1,071 Leasehold improvements 1,782 1,941 Accumulated depreciation (827 ) (677 ) Property and equipment, net $ 2,482 $ 3,538 Depreciation expenses relating to property and equipment were $582 thousand, $356 thousand, and $175 thousand for the years ended December 31, 2020, 2019 and 2018, respectively.

Patent License Agreement

Patent License Agreement	12 Months Ended
	Dec. 31, 2019
Patent License Agreement [Abstract]
Patent License Agreement	4. Patent License Agreement On November 23, 2016, the Company entered into a license agreement with the Board of Trustees of the University of Illinois (“the University”), which was amended on March 24, 2017. Pursuant to the license agreement, as amended, the University licensed patent rights to the Company, with rights of sublicense, to make, have made, use, import, sell and offer for sale products covered by certain patent rights owned by the University. The rights licensed to the Company are exclusive, worldwide, non-transferable rights, for all fields of use. Under the terms of the agreement the Company paid a one-time only, non-refundable license issue fee in the amount of $0.5 million which was charged to research and development expense in the fourth quarter of 2016. The Company is also obligated to pay annual maintenance fees to the University. All annual minimum payments are fully creditable against any royalty payments made by the Company. Under the terms of the agreement, the Company must pay the University royalty percentage on all net sales of products and a share of sublicensing revenues. In addition, the University is eligible to receive milestone payments of up to $2.6 million related to the initiation and execution of clinical trials and the first commercial sale of a product in another country. To date, the Company has made milestone payments totaling $0.6 million, of which $0 was incurred during 2020. The Company will be responsible for any future patent prosecution costs that may arise. The term of the license agreement will continue until the later of (i) the expiration of the last valid claim within the patent rights covering the product in such country, (ii) the expiration of market exclusivity in such country and (iii) the 10th anniversary of the first commercial sale in such country. The University may terminate the agreement in the event (i) the Company fails to pay any amount or make any report when required to be made and fails to cure such failure within thirty (30) days after receipt of notice from the University, (ii) is in breach of any provision of the agreement and fails to remedy within forty-five (45) days after receipt of notice, (iii) makes a report to the University under the agreement that is determined to be materially false, (iv) declares insolvency or bankruptcy or (v) takes an action that causes patent rights or technical information to be subject to lien or encumbrance and fails to remedy any such breach with in forty-five (45) days of receipt of notice from the University. The Company may terminate the agreement at any time on written notice to the University at least ninety (90) days prior to the termination date specified in the notice. Upon expiration or termination of the agreement, all rights revert to the University.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses are comprised as follows (in thousands): December 31, 2020 December 31, 2019 Accrued external research $ 3,219 $ 2,737 Accrued professional fees and other 3,920 1,487 Accrued external clinical study costs 5,683 7,996 Accrued compensation expense 3,664 3,183 Accrued expenses $ 16,486 $ 15,403

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	6. Leases We adopted ASC 842 as of January 1, 2019. Prior period amounts have not been adjusted and continue to be reported in accordance with our historic accounting under ASC 840. Pursuant to a lease agreement dated January 10, 2014 (the “Lease”), on April 1, 2014, the Company leased office and lab space with a free rent period and escalating rent payments; the Lease had an expiration date of July 31, 2017. The Lease was amended on January 27, 2016 to lease new larger office and lab space beginning in August 2016 with a discounted rent period and escalating rent payments and the Lease term was extended to December 31, 2022. The amendment also contained an option for a five-year On March 20, 2020, the Lease was amended to surrender three of the office spaces previously entered into above, with a termination date of May 31, 2020 and in consideration of a termination fee to be paid. The lease payments and term for the remaining occupied space will remain the same. Due to these changes in lease terms for the three office spaces, in March 2020 the Company modified the operating lease liabilities and operating lease assets of these three office spaces to reflect the new terms. In November 2018, the Company signed a new lease to secure approximately 60,000 square feet of laboratory and office space at 700 Park Offices Drive in Research Triangle Park, NC (“700 Lease”). The 700 Lease commenced on September 2, 2019 and has an expiration date of September 30, 2027 for the initial term with the Company having the option to renew for an additional 5 years. The term of the renewal option contained in the Lease was not included in the measurement of the operating lease asset and liability since exercise of the option was uncertain. As part of the 700 Lease, the Company obtained a standby letter of credit in the amount of $0.5 million related to the security deposit. This letter of credit is secured by money market funds at the financial institution. Therefore, these funds are classified as restricted cash on the balance sheet. The letter of credit will be reduced ratably on each anniversary of the commencement of the 700 Lease until the end of the lease term. The tables below reflect the Company’s lease position and weighted-average lease terms and discount rates for our operating leases as of December 31, 2020. Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, we use our incremental borrowing rate based on the information available at the lease commencement date. (in thousands) Classification on the Balance Sheet December 31, 2020 Assets Operating lease assets Operating lease assets $ 8,026 Total lease assets $ 8,026 Liabilities Current Operating Other current liabilities $ 988 Non-current Operating Operating lease liabilities 7,865 Total lease liabilities $ 8,853 Lease Term and Discount Rate December 31, 2020 Weighted-average remaining lease term (years) Operating leases 6.6 Weighted-average discount rate Operating leases 8.0 % The table below presents information related to the lease costs for operating leases (in thousands): Year Ended December 31, (in thousands) Classification 2020 2019 2018 Operating lease costs (a) Research and development $ 955 $ 609 $ 298 General and administrative 1,191 368 83 Total operating lease costs $ 2,146 $ 977 $ 381 (a) Includes variable lease costs which are immaterial The table below reconciles the undiscounted cash flow for each of the first five years and total of the remaining years to the operating lease liabilities recorded on the balance sheet as of December 31, 2020 (in thousands): Operating leases Years ending December 31, 2021 1,657 2022 1,703 2023 1,634 2024 1,679 2025 1,725 Thereafter 3,131 Total future minimum lease payments $ 11,529 Less: present value adjustment (2,676 ) Total operating lease liabilities $ 8,853 Cash payments included in the measurement of our operating leases were $1,683 thousand for the twelve months ended December 31, 2020.

Loan Payable

Loan Payable	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Loan Payable	7. Loan Payable On May 29, 2020, the Company entered into a loan and security agreement (the “Loan Agreement”) with Hercules Capital, Inc. (“Hercules”), under which Hercules has agreed to lend the Company up to $100.0 million, to be made available in a series of tranches, subject to certain terms and conditions. The first tranche totals $30.0 million, of which the Company received $20.0 million at closing. Upon initiation of the phase 3 trial for metastatic colorectal cancer and upon receiving FDA approval for small cell lung cancer (“the Performance Milestone”), the second tranche of $20.0 million will become available to the Company for drawdown through December 15, 2021. The third tranche of $30.0 million will be available through December 31, 2022. The fourth tranche of $20.0 million will be available at Hercules’ approval through December 31, 2022. If the Company achieves the Performance Milestone and does not draw further on the loan, no financial covenants are required. If the Company achieves the Performance Milestone and draws any advance other than the first tranche, financial covenants will apply. As of December 31, 2020, no financial covenants apply as the Company has only drawn down on the first tranche. Amounts borrowed under the Loan Agreement will bear an interest rate equal to the greater of either (i) (a) the prime rate as reported in The Wall Street Journal, plus (b) 6.40%, and (ii) 9.65%. The Company will make interest only payments through June 1, 2022. The interest only period may be extended through January 1, 2023 upon satisfaction of the Performance Milestone. Following the interest only period, the Company will repay the principal balance and interest of the advances in equal monthly installments through June 1, 2024. The Company may prepay advances under the Loan Agreement, in whole or in part, at any time subject to a prepayment charge equal to (a) 3.0% of the prepayment amount in the first year; (b) 2.0% of the prepayment amount in the second year; and (c) 1.0% of the prepayment amount in the third year. Upon prepayment or repayment of all or any of the advances under the Loan Agreement, the Company will pay (in addition to the prepayment charge) an end of term charge of 6.95% of the aggregate funded amount. With respect to the first tranche, the end of term charge of $2.1 million will be payable upon any prepayment or repayment. To the extent that the Company is provided additional advances under the Loan Agreement, the 6.95% end of term charge will be applied to such additional amounts. These amounts will be accrued over the term of the loan using effective-interest method. The Loan Agreement is secured by substantially all of the Company’s assets, including intellectual property, subject to certain exemptions. The Company out-licensed lerociclib as permitted in the Loan Agreement and the Company may out-license rintodestrant upon approval of the licensing terms by Hercules. The Company incurred financing expenses of $0.4 million related to the Loan Agreement which are recorded as debt issuance costs and as a direct reduction to long-term debt on the Company’s balance sheet. Additionally, the Company is treating $0.2 million of the upfront facility fee that related to the initial $20.0 million drawn as a debt discount and treating it in the same way as debt issuance costs. The remainder of the facility fee is related to future undrawn tranches and is accounted for as a deferred financing charge. Upon issuance, the first tranche was recorded as a liability with an initial carrying value of $19.4 million, net of debt discount and debt issuance costs. The initial carrying value will be accreted to the repayment amount, which includes the outstanding principal plus the end of term charge, through interest expense using the effective-interest method over the term of the debt. During the twelve months ended December 31, 2020, the Company recognized $1.8 million of interest expense related to the Loan Agreement, which is reflected in other income (expense), net on the unaudited condensed statements of operations. As of December 31, 2020 the future principal payments due under the Loan Agreement, excluding interest, are as follows: Amount 2021 — 2022 4,631 2023 9,972 2024 5,397 Total principal outstanding 20,000 End of term charge 395 Unamortized debt issuance costs (502 ) Total 19,893

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity Common stock The Company’s common stock has a par value of $0.0001 per share and consists of 120,000,000 authorized shares as of December 31, 2020 and 2019, respectively. Holders of common stock are entitled to one vote per share and are entitled to receive dividends, as if and when declared by the Company’s Board of Directors. The Company has reserved authorized shares of common stock for future issuance at December 31, 2020 and December 31, 2019 as follows: December 31, 2020 December 31, 2019 Common stock options outstanding 6,644,780 5,744,036 Options available for grant under Equity Incentive Plans 932,051 938,738 7,576,831 6,682,774 Preferred stock Upon completion of the IPO, all outstanding preferred stock was automatically converted into 18,933,053 shares of common stock. The Company is also authorized to issue 5,000,000 shares of undesignated preferred stock in one or more series. As December 31, 2020, no shares of preferred stock were issued or outstanding.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation 2011 Equity Incentive Plan In March 2011, the Company adopted the 2011 Equity Incentive Plan (the “Plan”). As amended, 4,400,640 shares of common stock were reserved for issuance under the 2011 Plan. Eligible plan participants included employees, directors, officers, consultants and advisors of the Company. The 2011 plan permitted the granting of incentive stock options, nonqualified stock options and other stock- based awards. 2017 Equity Incentive Plan In May 2017, the Company adopted the 2017 Equity Incentive Plan (the “2017 Plan”). The 2017 Plan provided for the direct award or sale of the Company’s common stock and for the grant of up to 1,932,000 stock options to employees, directors, officers, consultants and advisors of the Company. The 2017 Plan provides for the grant of incentive stock options, non-statutory stock options or restricted stock. Effective January 1, 2018, and in accordance with the “evergreen” provision of the 2017 plan, an additional 1,066,692 shares were made available for issuance. Effective January 1, 2019, and in accordance with the “evergreen” provision of the 2017 plan, an additional 1,096,553 shares were made available for issuance. Effective January 1, 2020, and in accordance with the “evergreen” provision of the 2017 plan, an additional 1,096,553 shares were made available for issuance. Under both the 2011 Plan and the 2017 Plan, options to purchase the Company’s common stock may be granted at a price no less than the fair market value of a share of common stock on the date of grant. The fair value shall be the closing sales price for a share as quoted on any established securities exchange for such grant date or the last preceding date for which such quotation exists. Vesting terms of options issued are determined by the Board of Directors or Compensation Committee of the Board. The Company’s stock options vest based on terms in the stock option agreements. Stock options have a maximum term of ten years. As of December 31, 2020, there were a total of 932,051 shares of common stock available for future issuance under the 2017 Plan. Stock-based Compensation During the years ended December 31, 2020, 2019 and 2018, the Company recorded employee share-based compensation expense of $18,770, $16,351, and $8,157, respectively. The Company recorded non-employee share-based compensation expense of $0, $98, and $2,068 during the years ended December 31, 2020, 2019 and 2018, respectively. Total share-based compensation expense included in the statements of operations is as follows: Year Ended December 31, 2020 2019 2018 in thousands Research and development $ 6,902 $ 6,261 $ 5,218 General and administrative 11,868 10,188 5,007 Total stock-based compensation expense $ 18,770 $ 16,449 $ 10,225 The fair value of each option grant is estimated on the grant date using the Black-Scholes option-pricing model, using the following weighted average assumptions: Year Ended December 31, 2020 2019 2018 Expected volatility 74.8 - 81.0% 74.2 - 82.1% 74.9 - 86.5% Weighted-average risk free rate 0.3-1.7% 1.4 - 2.6% 2.3 - 3.0% Dividend yield —% —% —% Expected term (in years) 6.02 6.02 6.04 Weighted-average grant-date fair value per share $ 12.17 $ 14.94 $ 26.42 The expected term of stock options represents the weighted-average period the stock options are expected to remain outstanding and is based on the option vesting term, contractual terms and industry peers as the Company did not have sufficient historical information to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior. The expected stock price volatility assumptions for the Company’s stock options were determined by examining the historical volatilities for industry peers as the Company does not have sufficient history to estimate volatility using only its common stock. In 2019, the Company began incorporating its historical stock price in conjunction with selected similar publicly traded companies. The Company plans to continue to use the guideline peer group volatility information until the historical volatility of its common stock is sufficient to measure expected volatility for future option grants. The risk-free interest rate assumption at the date of grant is based on the U.S. Treasury instruments whose term was consistent with the expected term of the Company’s stock options. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. Stock option activity during 2020 is as follows: Weighted average Weighted Remaining average contractual Aggregate Options exercise for intrinsic outstanding price life (Years) value (in thousands) Balance as of December 31, 2019 5,744,036 $ 16.88 7.5 $ 72,251 Cancelled (635,797 ) $ 30.94 Granted 2,039,037 $ 18.32 Exercised (502,496 ) $ 4.59 Balance as of December 31, 2020 6,644,780 $ 16.91 7.3 $ 35,464 Exercisable at December 31, 2020 3,542,190 $ 12.94 6.0 $ 31,686 Vested at December 31, 2020 and expected to vest 6,644,780 $ 16.91 7.3 $ 35,464 As of December 31, 2020, there was $38,834 of total unrecognized share-based compensation costs, which is expected to be recognized over a weighted-average period of 2.42 years. Prior to our initial public offering, the fair value of our common shares underlying our stock options was estimated on each grant date by our board of directors. In order to determine the fair value of our common shares underlying granted stock options, our board of directors considered, among other things, timely valuations of our common shares prepared by an unrelated third-party valuation firm in accordance with the guidance provided by the American Institute of Certified Public Accountants Practice Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation. Since the IPO, the board of directors has determined the fair value of each common share underlying share-based awards based on the closing price of the common shares as reported by Nasdaq on the date of grant.

License Revenue

License Revenue	12 Months Ended
	Dec. 31, 2020
Revenue Recognition [Abstract]
License Revenue	10. License Revenue ARC License Agreement On May 22, 2020, the Company entered into an exclusive license agreement with ARC Therapeutics, LLC (“ARC”), a company primarily owned by a related party, whereby the Company granted to ARC an exclusive, worldwide, royalty-bearing license, with the right to sublicense, solely to make, have made, use, sell, offer for sale, import, export, and commercialize products related to its cyclin dependent kinase 2 (“CDK2”) inhibitor compounds. At close, the Company received consideration in the form of an upfront payment of $1.0 million and an equity interest in ARC equal to 10% of its issued and outstanding units valued at $1.1 million. In addition, the Company may receive a future development milestone payment totaling $2.0 million and royalty payments in the mid-single digits based on net sales of the licensed compound after commercialization. The Company has right of first negotiation to re-acquire these assets. The Company assessed the license agreement in accordance with ASC 606 and identified one performance obligation in the contract, which is the transfer of the license, as ARC can benefit from the license using its own resources. The Company recognized $2.1 million in license revenue consisting of the upfront payment and the 10% equity interest in ARC upon the effective date as the Company determined the license was a right to use the intellectual property and the Company had provided all necessary information to ARC to benefit from the license. The Company considers the future potential development milestones and sales-based royalties to be variable consideration. The development milestone is excluded from the transaction price because it determined the payment to be fully constrained under ASC 606 due to the inherent uncertainty in the achievement of such milestone due to factors outside of the Company’s control. As sales-based royalties are all related to the license of the intellectual property, the Company will recognize revenue in the period when subsequent sales are made pursuant to the sales-based royalty exception. The Company will re-evaluate the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. Genor License Agreement On June 15, 2020, the Company entered into an exclusive license agreement with Genor Biopharma Co. Inc. (“Genor”) for the development and commercialization of lerociclib in the Asia-Pacific region, excluding Japan (the “Genor Territory”). Under the license agreement, the Company granted to Genor an exclusive, royalty-bearing, non-transferable license, with the right to grant sublicenses, to develop, obtain, hold and maintain regulatory approvals for, and commercialize lerociclib, in the Genor Territory. Under the license agreement, Genor agreed to pay the Company a non-refundable, upfront cash payment of $6.0 million with the potential to pay an additional $40.0 million upon reaching certain development and commercial milestones. In addition, Genor will pay the Company tiered royalties ranging from high single to low double-digits based on annual net sales of lerociclib in the Genor Territory. The upfront cash payment was received in July 2020. In September 2020, the Company transferred to Genor the related technology and know-how that is necessary to develop, seek regulatory approval for, and commercialize lerociclib in the Genor Territory. Genor will be responsible for the development of the product in the Genor Territory and will be responsible, at its sole cost, for obtaining supply of lerociclib to meet its development, regulatory approval, and commercialization obligations under the agreement. The Company assessed the license agreement in accordance with ASC 606 and identified the following promises under the contract: (i) to transfer the license, (ii) technology transfer and the transfer of related know-how to occur within 60 days of the effective date of the license agreement, and (iii) the sale and delivery of certain existing inventory specified in the agreement. The Company assessed the promised goods and services to determine if they are distinct. Based on this assessment, the Company determined that Genor cannot benefit from the license separate from the technology transfer and related know-how as they are highly interrelated and therefore not distinct. Accordingly, the transfer of the license and the related technology and know-how represent one combined performance obligation. In accordance with ASC 606, the Company determined the transaction price at contract inception. The Company considers the future potential development and sales milestones, as well as the sales-based royalties to be variable consideration. The Company excluded the regulatory-based development and sales milestones from the transaction price because it determined such payments to be fully constrained under ASC 606 due to the inherent uncertainty in the achievement of such milestone payments and high susceptibility to factors outside our control. As the sales-based royalties are all related to the license of the intellectual property, the Company will recognize revenue in the period when subsequent sales are made pursuant to the sales-based royalty exception. The Company will re-evaluate the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. Based on the foregoing, the Company determined that the $ 6.0 million non-refundable, upfront payment and the $ 0.6 million owed upon the delivery of existing inventory constituted the entirety of consideration to be included in the transaction price . The Company then allocated the transaction price to the performance obligations based on the relative stand-alone selling price of each distinct obligation. The Company determined the stand-alone selling prices to equal the amounts paid for each performance obligation. Revenue is recognized for each performance obligation based at a point in time in which control has been transferred. The performance obligation for the transfer of the license and related technology and know-how does not occur until the delivery of the related know-how has been satisfied. This delivery occurred in September 2020 at which point $6.0 million was recognized as revenue. The delivery of existing inventory occurred in the fourth quarter of 2020 at which point $0.6 million was recognized as revenue. EQRx License Agreement On July 22, 2020, the Company entered into an exclusive license agreement with EQRx, Inc. (“EQRx”) for the development and commercialization of lerociclib in the U.S., Europe, Japan and all other global markets, excluding the Asia-Pacific region (except Japan) (the “EQRx Territory”). Under the license agreement, the Company granted to EQRx an exclusive, royalty-bearing, non-transferable license, with the right to grant sublicenses, to develop, obtain, hold and maintain regulatory approvals for, and commercialize lerociclib in the EQRx Territory. Under the license agreement, EQRx agreed to pay the Company a non-refundable, upfront cash payment of $20.0 million with the potential to pay an additional $290.0 million upon reaching certain development and commercial milestones. In addition, EQRx will pay the Company tiered royalties ranging from mid-single digits to mid-teens based on annual net sales of lerociclib in the EQRx Territory. The upfront cash payment was received in August 2020. In September 2020, the Company transferred to EQRx the related technology and know-how that is necessary to develop, seek regulatory approval for, and commercialize lerociclib in the EQRx Territory. EQRx will be responsible for the development of the product in the EQRx Territory. The Company will continue until completion, as the clinical trial sponsor, its two primary clinical trials at EQRx’s sole cost and expense. EQRx will reimburse the Company for all of its out-of-pocket costs incurred after the effective date of the license agreement in connection with these clinical trials. The Company will invoice EQRx within 30 days following the end of the quarter, and EQRx will pay within 30 days after its receipt of such invoice. The Company assessed the license agreement in accordance with ASC 606 and identified the following promises under the contract: (i) to transfer the license, (ii) technology transfer and the transfer of related know-how to occur within 60 days of the effective date of the license agreement, (iii) the Company’s continuation as clinical trial sponsor for two primary clinical trials, and (iv) the sale and delivery of certain existing inventory specified in the agreement. The Company assessed the promised goods and services to determine if they are distinct. Based on this assessment, the Company determined that EQRx cannot benefit from the license separate from the technology transfer and related know-how as they are highly interrelated and therefore not distinct. Accordingly, the transfer of the license and the related technology and know-how represent one combined performance obligation. In accordance with ASC 606, the Company determined the transaction price at contract inception. The Company considers the future potential development and sales milestones, as well as the sales-based royalties to be variable consideration. The Company excluded the regulatory-based development and sales milestones from the transaction price because it determined such payments to be fully constrained under ASC 606 due to the inherent uncertainty in the achievement of such milestone payments and high susceptibility to factors outside our control. As the sales-based royalties are all related to the license of the intellectual property, the Company will recognize revenue in the period when subsequent sales are made pursuant to the sales-based royalty exception. We concluded that the reimbursement of costs incurred for the two primary clinical trials qualifies for the practical expedient under ASC 606, which allows the Company to recognize revenue in the amount for which we have a right to invoice if our right to consideration is an amount that corresponds directly to the value of performance completed to date. We, therefore, will not allocate that transaction price to the performance obligations. The Company will re-evaluate the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. Based on the foregoing, the Company determined that the $20.0 million non-refundable, upfront payment and the $0.7 million owed upon delivery of existing inventory constituted the entirety of consideration to be included in the transaction price. The Company then allocated the transaction price to the performance obligations based on the relative stand-alone selling price of each distinct obligation. The Company determined the stand-alone selling prices to equal the amounts paid for each performance obligation. Revenue is recognized for the transfer of the license and the related technology and know-how and delivery of existing inventory performance obligations based at a point in time in which control has been transferred. The performance obligation for the transfer of the license and the related technology and know-how does not occur until the delivery of the related technology and know-how has been satisfied. This delivery occurred in September 2020 at which point $ 20.0 million was recognized as revenue. Revenue is recognized for the reimbursement of costs associated with the two primary clinical trials based on the amount to be invoiced to EQRx for work completed from the effective date of the license agreement through December 31 , 2020. During the twelve -months ended December 3 1 , 2020, the Company recognized revenue of $ 1.3 million associated with this performance obligation , of which we have invoiced and received payment for $ 0.2 million . As of December 31, 2020, the remaining $ 1.1 million has not been invoiced and a contract asset for this amount was recognized on the balance sheet. The delivery of existing inventory occurred in the fourth quarter of 2020 at which point $ million was recognized as revenue . Simcere License Agreement On August 3, 2020, the Company entered into an exclusive license agreement with Nanjing Simcere Dongyuan Pharmaceutical Co., Ltd (“Simcere”) for the development and commercialization of trilaciclib in all indications in Greater China (mainland China, Hong Kong, Macau, and Taiwan) (the “Simcere Territory”). Under the license agreement, the Company granted to Simcere an exclusive, royalty-bearing, non-transferable license, with the right to grant sublicenses, to develop, obtain, hold and maintain regulatory approvals for, and commercialize trilaciclib in the Simcere Territory. Under the license agreement, Simcere agreed to pay the Company a non-refundable, upfront cash payment of $14.0 million with the potential to pay an additional $156.0 million upon reaching certain development and commercial milestones. In addition, Simcere will pay the Company tiered low double-digit royalties on annual net sales of trilaciclib in the Simcere Territory. The upfront cash payment of $14.0 million (less applicable withholding taxes of $1.4 million) was received in September 2020. In return, the Company will furnish to Simcere the related technology and know-how that is necessary to develop, seek regulatory approval for, and commercialize trilaciclib in the Simcere Territory. Simcere will be responsible for all development and commercialization costs in its territory and may be able to participate in global clinical trials as agreed upon by the companies. No plans have currently been established for any combined participation in global clinical trials, however, each company will be responsible for the associated costs in their respective territories. The license agreement also provides for the companies to enter into a separate supply agreement which shall be entered into by the companies following the effective date of the license agreement. The supply agreement was executed in January 2021. The Company assessed the license agreement in accordance with ASC 606 and identified the following promises under the contract: (i) to transfer the license, (ii) technology transfer and the transfer of related know-how to occur promptly following the effective date of the license agreement, (iii) participation in the joint steering committee (“JSC”), and (iv) participation in the joint development committee (“JDC”). The Company determined that Simcere cannot benefit from the license separate from the technology transfer and related technology and know-how as they are highly interrelated and therefore not distinct. Accordingly, the transfer of the license and the related technology and know-how were combined as a single performance obligation. The Company assessed the participation on the JSC and the JDC and concluded that the promises are immaterial in the context of the license agreement and therefore are excluded as performance obligations. The Company assessed the supply agreement to determine whether it is a distinct performance obligation. The license agreement provides for the companies to enter into a supply agreement following the effective date of the license agreement. Simcere may notify the Company of its desire to manufacture, or have manufactured using a third-party CMO, supply of trilaciclib at which point the related manufacturing know-how will be transferred to Simcere at its sole cost and expense. Based on the foregoing, the supply agreement is considered an option and was assessed to determine whether a material right exists. The Company determined that the negotiated price for performing services under a supply agreement are at standalone selling prices, and as such these services would not be provided at a significant or incremental discount and is not considered a material right. In accordance with ASC 606, the Company determined the transaction price at contract inception. The Company considers the future potential development and sales milestones, as well as the sales-based royalties to be variable consideration. The Company excluded the regulatory-based development and sales milestones from the transaction price because it determined such payments to be fully constrained under ASC 606 due to the inherent uncertainty in the achievement of such milestone payments and high susceptibility to factors outside our control. As the sales-based royalties are all related to the license of the intellectual property, the Company will recognize revenue in the period when subsequent sales are made pursuant to the sales-based royalty exception. The Company will re-evaluate the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. Based on the foregoing, the Company determined that the $14.0 million non-refundable, upfront payment constituted the entirety of consideration to be included in the transaction price. As there is one combined performance obligation, the Company allocated the entirety of the transaction price to the one performance obligation. Revenue is recognized based at a point in time in which control has been transferred. The performance obligation for the transfer of the license and related technology and know-how does not occur until the delivery of the related technology and know-how has been satisfied. This delivery occurred in December 2020 at which point $14.0 million was recognized as revenue.

Net Loss Per Common Share

Net Loss Per Common Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Loss Per Common Share	11. Net Loss per Common Share Basic net loss per common share is computed using the weighted average number of common shares outstanding during the period including nominal issuances of common stock warrants. Diluted net loss per common share is computed using the sum of the weighted average number of common shares outstanding during the period and, if dilutive, the weighted average number of potential shares of common stock, including the assumed exercise of stock options, stock warrants and unvested restricted common stock. For the years ended December 31, 2020, 2019 and 2018, the following potentially dilutive securities have been excluded from the computations of diluted weighted-average shares outstanding because the effect would be anti-dilutive: Year Ended December 31, 2020 2019 2018 Stock options issued and outstanding 6,576,688 5,443,730 4,318,731 6,576,688 5,443,730 4,318,731 Amounts in the table above reflect the common stock equivalents of the noted instruments.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes Income taxes are accounted for using the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statements carrying amounts of assets and liabilities and their respective tax bases, operating loss carryforwards, and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In accordance with FASB ASC 740, Accounting for Income Taxes The components of income tax expense (benefit) attributable to continuing operations are as follows: Year ended December 31, 2020 2019 2018 Current Expense: Federal $ — $ — $ — State — — — Foreign 1,410 — — 1,410 — — Deferred Expense: Federal — — — State Foreign — — — $ 1,410 $ — $ — The differences between the company’s income tax expense attributable to continuing operations and the expense computed at the 21% U.S. statutory income tax rate were as follows (in thousands): Year ended December 31, 2020 2019 2018 Federal income tax benefit at statutory rate: $ (20,547 ) $ (25,714 ) $ (17,910 ) Increase (reduction) in income tax resulting from: State Income Taxes (1,779 ) (2,369 ) (1,518 ) Increase in Valuation Allowance 23,782 29,499 26,614 Write off Sec. 382 Limited Carryforwards — 1,858 — Stock Compensation 1,341 461 (3,011 ) Research and Development Credit (3,091 ) (3,529 ) (4,187 ) Foreign Withholding Tax 1,410 — — Other 294 (206 ) 12 $ 1,410 $ — $ — The tax effects of temporary differences and operating loss carryforwards that gave rise to significant portions of the deferred tax assets and deferred tax liabilities were as follows at December 31, 2020 and 2019 (in thousands): Year ended December 31, 2020 2019 Deferred tax assets Accrued expenses $ 2,863 $ 2,205 Operating lease liabilities 2,034 2,348 Stock compensation 7,147 4,865 Capitalized patents and licenses - 2,156 R&D credits 13,965 10,874 Net operating loss carryforwards 85,842 65,869 Other 20 6 Deferred tax assets 111,871 88,323 Deferred tax liabilities Operating lease assets (1,844 ) (2,263 ) Other (245 ) (60 ) Deferred tax liabilities (2,089 ) (2,323 ) Valuation allowance (109,782 ) (86,000 ) Net deferred tax assets $ — $ — At December 31, 2020 and December 31, 2019, the Company evaluated all significant available positive and negative evidence, including the existence of losses in recent years and management’s forecast of future taxable income, and, as a result, determined it was more likely than not that federal and state deferred tax assets, including benefits related to net operating loss carryforwards, would not be realized. The valuation allowance was increased from $86.0 million at December 31, 2019 to $109.8 million at December 31, 2020. The increase in valuation allowance was due primarily to the increase in net operating loss carryforwards and income tax credits. The table below summarizes changes in the deferred tax valuation allowance (in thousands): 2020 2019 2018 Balance at beginning of year $ 86,000 $ 56,501 $ 29,887 Charges to costs and expenses 25,170 31,357 26,614 Write-offs (1,388 ) (1,858 ) — Balance at end of year 109,782 86,000 56,501 At December 31, 2020, the Company has federal net operating loss carryforwards (“NOLs”) of approximately $373.1 million, which are available to offset future taxable income. Of the $373.1 million available, $95.4 million will begin to expire in 2029. The remaining $277.6 million has an indefinite carryforward period. Under the Tax Cuts and Jobs Act (“Tax Act”), federal NOLs arising after December 31, 2017 may be carried forward indefinitely. However, for NOLs arising after December 31, 2017, NOL carryforwards will be limited to 80% of taxable income. The Company’s NOLs generated in 2017 and in prior years will not be subject to the 80% limitation under the Tax Act. In addition, the Company has state net operating loss carryforwards totaling approximately $ 379.8 million , which are available to offset future state taxable income. State net operating losses begin to expire in 202 4 . Because the Company has incurred cumulative net operating losses since inception, all tax years remain open to examination by U.S. federal and state income tax authorities. As of December 31, 2020 , the Company also had federal research and development (R&D) credit carryforwards of approximately $ million available to offset future income tax which begin to expire in 203 5 . In accordance with FASB ASC 740, Accounting for Income Taxes Section 382 Limitation The Company’s ability to utilize its net operating loss and research and development 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. In April 2019, the Company c ompleted an evaluation study as to whether an “ownership change” had occurred and determined that the limitation would be $8.0 million on federal net operating loss carryforwards, $1.2 million on state net operating loss carryforwards, and $0.1 million on R&D tax credit carryforwards. The carryforward amounts reported above have already been reduced for these limitations. The Company continues to maintain a valuation allowance on the remaining NOLs as it believes that it is more likely than not all of the deferred tax asset associated with the NOLs will not be realized regardless of whether an “ownership change” has occurred.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	13. Related Party Transactions The Company paid approximately $ 6 thousand The Company granted an exclusive, worldwide, royalty-bearing license of its CDK2 inhibitor compounds to ARC Therapeutics, LLC (“ARC”), a company primarily owned by a related party, in exchange for cash and equity in ARC with a total value of approximately $2.1 million, which resulted in the recognition of related party revenue as discussed in Note 10. The Company entered into a senior advisor agreement with John E. (Jack) Bailey, Jr., a member of the Board of Directors, effective October 1, 2020. Pursuant to the terms of the agreement, Mr. Bailey received $60,000 per month for his services through December 31, 2020. Mr. Bailey became the Company’s President and Chief Executive Officer effective January 1, 2021. The Company entered into a senior advisor agreement on September 29, 2020 with Mark A. Velleca, M.D., Ph.D., a member of the Board of Directors, with an effective date of January 1, 2021. Pursuant to the terms of the agreement, Dr. Velleca will receive $200,000 annually, paid in equal quarterly installments, for his services. The senior advisory agreement will expire on December 31, 2023.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events (Unaudited) From January 14, 2021 through February 9, 2021, the Company utilized a Sales Agreement for “at the market offerings” with Cowen to sell 3,513,027 shares of common stock, resulting in $86.4 million in net proceeds. As of February 9, 2021, there is no remaining availability under the sales agreement with Cowen. On February 23, 2021, the Board of Directors adopted the G1 Therapeutics, Inc. Inducement Equity Incentive Plan (the “Inducement Plan”), to be effective immediately, pursuant to which we reserved 500,000 shares of our common stock to be used exclusively for grants of awards (as defined below) to individuals who were not previously employees or directors of G1, or who are returning to employment following a bona fide common stock or other property pursuant to the Inducement Plan, including non-statutory stock options and restricted stock unit awards. In addition, the Compensation Committee adopted forms of agreements for use with the Inducement Plan. Complete copies of the Inducement Plan, along with the form of Stock Option Agreement under the Inducement Plan, and the form of Restricted Stock Unit Agreement under the Inducement Plan, is filed herewith as Exhibit [10.7], and is incorporated herein by reference. The above summary of the terms of the Inducement Plan and the forms of agreement does not purport to be complete and is qualified in its entirety by reference to such exhibits.

Quarterly Results of Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	15. Quarterly Results of Operations (Unaudited) The following table contains quarterly financial information for 2020 and 2019. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. Three Months Ended (unaudited) (in thousands, except share and per share amounts) March 31, June 30, September 30, December 31, 2020 2020 2020 2020 License Revenue $ - $ 2,140 $ 26,599 $ 16,546 Total operating expenses 31,821 32,962 36,344 40,634 Loss from operations (31,821 ) (30,822 ) (9,745 ) (24,088 ) Total other income (expense), net 798 (388 ) (998 ) (780 ) Loss before income taxes (31,023 ) (31,210 ) (10,743 ) (24,868 ) Income tax expense — — 931 479 Net loss $ (31,023 ) $ (31,210 ) $ (11,674 ) $ (25,347 ) Net loss per share, basic and diluted $ (0.82 ) $ (0.83 ) $ (0.31 ) $ (0.67 ) Weighted average common shares outstanding, basic and diluted 37,659,722 37,786,208 38,009,204 38,053,609 March 31, June 30, September 30, December 31, 2019 2019 2019 2019 License Revenue $ - $ - $ - $ - Total operating expenses 25,881 32,583 34,024 36,553 Loss from operations (25,881 ) (32,583 ) (34,024 ) (36,553 ) Total other income (expense), net 1,929 1,893 1,660 1,112 Loss before income taxes (23,952 ) (30,690 ) (32,364 ) (35,441 ) Income tax expense — — — — Net loss $ (23,952 ) $ (30,690 ) $ (32,364 ) $ (35,441 ) Net loss per share, basic and diluted $ (0.64 ) $ (0.82 ) $ (0.86 ) $ (0.94 ) Weighted average common shares outstanding, basic and diluted 37,396,980 37,470,926 37,540,380 37,586,218

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company has prepared the accompanying financial statements in conformity with generally accepted accounting principles in the United States of America (“U.S. GAAP”).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and the accompanying notes. Actual results could differ from those estimates. These estimates include the Company’s common stock valuation, stock compensation, and deferred tax asset valuation allowance.
Revenue Recognition	Revenue Recognition For elements of those arrangements that we determine should be accounted for under ASC 606, Revenue from Contracts with Customers (“ASC 606”), we assess which activities in our license or collaboration agreements are performance obligations that should be accounted for separately and determine the transaction price of the arrangement, which includes the assessment of the probability of achievement of future milestones and other potential consideration. For arrangements that include multiple performance obligations, such as granting a license or performing manufacturing or research and development activities, we allocate the transaction price based on the relative standalone selling price and recognize revenue that is allocated to the respective performance obligation when (or as) control is transferred to the customer and the performance obligation is satisfied. Accordingly, we develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. These key assumptions may include revenue forecasts, clinical development timelines and costs, discount rates and probabilities of clinical and regulatory success. Licenses of Intellectual Property If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue associated with the bundled performance obligation. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of progress and related revenue recognition. Milestone Payments At the inception of each arrangement that includes developmental and regulatory milestone payments, the Company evaluates whether the achievement of each milestone specifically relates to the Company’s efforts to satisfy a performance obligation or transfer a distinct good or service within a performance obligation. The Company evaluates each milestone to determine when and how much of the milestone to include in the transaction price. The Company first estimates the amount of the milestone payment that the Company could receive using either the expected value or the most likely amount approach. The Company primarily uses the most likely amount approach as that approach is generally most predictive for milestone payments with a binary outcome. Then, the Company considers whether any portion of that estimated amount is subject to the variable consideration constraint (that is, whether it is probable that a significant reversal of cumulative revenue would not occur upon resolution of the uncertainty). The Company updates the estimate of variable consideration included in the transaction price at each reporting date which includes updating the assessment of the likely amount of consideration and the application of the constraint to reflect current facts and circumstances. Royalties For arrangements 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 will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any revenue related to sales-based royalties or milestone payments based on the level of sales.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents at December 31, 2020 and 2019 consist of amounts on deposit in banks, including checking accounts, money market accounts and certificates of deposit. Cash deposits are all in financial institutions in the United States. As part of the lease for the new office space, the Company obtained a standby letter of credit in the amount of $0.5 million related to the security deposit. This letter of credit is secured by money market funds at the financial institution. Therefore, these funds are classified as restricted cash on the balance sheet. The letter of credit will be reduced ratably on each anniversary of the commencement of the lease until the end of the lease term.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents. Deposits with financial institutions are insured, up to certain limits, by the Federal Deposit Insurance Corporation (“FDIC”). The Company’s cash deposits often exceed the FDIC insurance limit; however, all deposits are maintained with high credit quality institutions and the Company has not experienced any losses in such accounts. The financial condition of financial institutions is periodically reassessed, and the Company believes the risk of any loss is minimal. The Company believes the risk of any loss on cash due to credit risk is minimal.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation is generally calculated using the straight-line method over the following estimated useful lives: Computer equipment 5 years Laboratory equipment 5 years Furniture and fixtures 7 years Leasehold improvements 7 years Costs associated with maintenance and repairs are charged to expense as incurred. Property and equipment held under leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the related asset.
Impairment of Long-Lived Assets	Impairment of Long-lived Assets The Company evaluates its long-lived assets for indicators of possible impairment by comparison of the carrying amounts to future net undiscounted cash flows expected to be generated by such assets when events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess carrying value of the asset over the asset’s fair value based on discounted estimates of future cash flows. For the years ended December 31, 2020, 2019 and 2018, the Company’s management evaluated its long-lived assets and determined no impairment charge was needed.
Research and Development	Research and Development Research and development expenses consist of costs incurred to further the Company’s research and development activities and include salaries and related employee benefits, manufacturing of pharmaceutical active ingredients and drug products, costs associated with clinical trials, nonclinical activities, regulatory activities, research-related overhead expenses and fees paid to expert consultants, external service providers and contract research organizations which conduct certain research and development activities on behalf of the Company. Costs incurred in the research and development of products are charged to research and development expense as incurred. Each reporting period, management estimated and accrued research and development expenses, including external clinical study costs associated with clinical trial activities. The process of estimating and accruing expenses involved reviewing contracts and purchase orders, identifying services that have been provided on the Company’s behalf, and estimating the level of service performed and the associated cost incurred for the service when the Company has not yet been invoiced or otherwise notified of the actual costs. Costs for clinical trial activities were estimated based on an evaluation of vendors’ progress towards completion of specific tasks, using data such as patient enrollment, clinical site activations or information provided by vendors regarding their actual costs incurred. Payments for these activities are based on the terms of individual contracts and payment timing may differ significantly from the period in which the services were performed. The Company determines accrual estimates through reports from and discussions with applicable personnel and outside service providers as to the progress or state of completion of trials, or the services completed. The estimates of accrued external clinical study costs as of each balance sheet date are based on the facts and circumstances known at the time.
Fair Value of Financial Instruments	Fair value of Financial Instruments The Company provides disclosure of financial assets and financial liabilities that are carried at fair value based on the price that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurements may be classified based on the amount of subjectivity associated with the inputs to fair valuation of these assets and liabilities using the following three levels: Level 1 Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2 Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability and inputs that are derived principally from or corroborated by observable market data by correlation or other means. Level 3 Unobservable inputs that reflect the Company’s estimates of the assumptions that market participants would use in pricing the asset or liability. The Company develops these inputs based on the best information available, including its own data. The carrying amounts of cash, cash equivalents, accounts payable and accrued liabilities approximate fair value because of their short-term nature. At December 31, 2020 and 2019 these financial instruments and respective fair values have been classified as follows (in thousands): Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant other unobservable inputs (Level 3) Balance at December 31, 2020 Assets Money market funds $ 190,180 $ — $ — $ 190,180 Certificates of Deposit 15,970 — — 15,970 Total assets at fair value: $ 206,150 $ — $ — $ 206,150 Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant other unobservable inputs (Level 3) Balance at December 31, 2019 Assets Money market funds $ 252,563 $ — $ — $ 252,563 Certificates of Deposit 15,873 — — 15,873 Total assets at fair value: $ 268,436 $ — $ — $ 268,436 During the twelve months ended December 31, 2020 and December 31, 2019, there were no changes in valuation methodology. The Loan Payable (discussed in Note 7), which is classified as a Level 3 liability, has a variable interest rate and the carrying value approximates its fair value. As of December 31, 2020, the carrying value was $19.9 million.
Patent Costs	Patent Costs Costs associated with the submission of patent applications are expensed as incurred given the uncertainty of the future economic benefits of the patents. Patent-related legal expenses included in general and administrative costs were approximately $2,761 thousand, $2,114 thousand, and $1,352 thousand for the years ended December 31, 2020, 2019 and 2018, respectively.
Income Taxes	Income Taxes Income taxes are accounted for using the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statements carrying amounts of assets and liabilities and their respective tax bases, operating loss carryforwards, and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 740, Accounting for Income Taxes
Stock-Based Compensation	Stock-Based Compensation The primary type of stock-based payments utilized by the Company are stock options. The Company accounts for stock-based employee compensation arrangements by measuring the cost of employee services received in exchange for all equity awards granted based on the fair value of the award on the grant date. The fair value of each employee stock option is estimated on the date of grant using an options pricing model. The Company currently uses the Black-Scholes valuation model to estimate the fair value of its share- based payments. The model requires management to make a number of assumptions including expected volatility, expected life, risk-free interest rate and expected dividends. The Company accounts for stock-based non-employee compensation arrangements by recording the expense of such services based on the fair value of the equity instrument as estimated using the Black-Scholes pricing model. The fair value of the equity instrument is charged to operating expense over the term of the service agreement. In accordance with the implementation of ASU No. 2018-07 on January 1, 2019, the fair value of non-employee stock options is no longer be re-measured each reporting period.
Segment Information	Segment Information The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. All of the Company’s assets are held in the United States.
Comprehensive Loss	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. There was no difference between net loss and comprehensive loss for each of the periods presented in the accompanying financial statements.
Leases	Leases We determine if an arrangement is a lease at inception. Operating lease assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating leases are included in operating lease assets, other current liabilities, and operating lease liabilities on our balance sheet at December 31, 2020. Operating lease assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date to determine the present value of future payments. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term.
Debt Issuance Costs	Debt Issuance Costs Debt issuance costs are amortized to interest expense over the estimated life of the related debt based on the effective interest method. In accordance with ASC 835, Interest, we present debt issuance costs on the condensed balance sheet as a direct deduction from the associated debt.
Coronavirus (COVID-19) Impact on Operations	Coronavirus (COVID-19) Impact on Operations The Company has implemented business continuity plans to address the COVID-19 pandemic and minimize disruptions to ongoing operations. Enrollment of patients in current and future clinical trials may be impacted by COVID-19. The Company does not anticipate significant supply chain delays or shortages as a result of the COVID-19 pandemic. COVID-19 travel limitations and government-mandated work-from-home or shelter-in-place orders, may reduce the number of in-person meetings with prescribers and fewer patient visits with physicians, potentially resulting in fewer new prescriptions. The established a COVID-19 response team which continually monitors the impact of COVID-19 on its operations. The COVID-19 response team manages workplace protocols that govern employees use of our office. To mitigate the impact of COVID-19 on its business, the Company put in place the following safety measures for its employees, patients, healthcare professionals, and suppliers to limit exposure: the Company substantially restricted travel, supplied personal protective equipment to employees, limited access to its headquarters and asked most of its staff to work remotely. In addition, the Company transitioned most of its employees to working remotely and added bandwidth and VPN capacity to its infrastructure. The Company will continue to monitor the impact of COVID-19 on its operations and report to the Board regularly on the progress of its response to the COVID-19 outbreak.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adoption of New Accounting Standards In August 2018, the FASB issued ASU No. 2018-15, Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). The FASB issued ASU 2018-15 to align the requirements for capitalizing implementation costs incurred in a cloud-based hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). ASU 2018-15 became effective for annual and interim reporting periods beginning after December 15, 2019. The Company adopted ASU 2018-15 on January 1, 2020 using the prospective method of adoption, and the adoption did not have a material impact to the financial statements.

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Property and Equipment Estimated Useful Lives	Depreciation is generally calculated using the straight-line method over the following estimated useful lives: Computer equipment 5 years Laboratory equipment 5 years Furniture and fixtures 7 years Leasehold improvements 7 years
Summary of Financials Instruments and Respective Fair Values	At December 31, 2020 and 2019 these financial instruments and respective fair values have been classified as follows (in thousands): Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant other unobservable inputs (Level 3) Balance at December 31, 2020 Assets Money market funds $ 190,180 $ — $ — $ 190,180 Certificates of Deposit 15,970 — — 15,970 Total assets at fair value: $ 206,150 $ — $ — $ 206,150 Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant other unobservable inputs (Level 3) Balance at December 31, 2019 Assets Money market funds $ 252,563 $ — $ — $ 252,563 Certificates of Deposit 15,873 — — 15,873 Total assets at fair value: $ 268,436 $ — $ — $ 268,436

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consists of the following (in thousands): December 31, 2020 December 31, 2019 Computer equipment $ 327 $ 332 Laboratory equipment 334 871 Furniture and fixtures 866 1,071 Leasehold improvements 1,782 1,941 Accumulated depreciation (827 ) (677 ) Property and equipment, net $ 2,482 $ 3,538

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2020
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses are comprised as follows (in thousands): December 31, 2020 December 31, 2019 Accrued external research $ 3,219 $ 2,737 Accrued professional fees and other 3,920 1,487 Accrued external clinical study costs 5,683 7,996 Accrued compensation expense 3,664 3,183 Accrued expenses $ 16,486 $ 15,403

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Summary of Lease Position and Weighted-Average Lease Term and Discount Rate of Operating Leases	The tables below reflect the Company’s lease position and weighted-average lease terms and discount rates for our operating leases as of December 31, 2020. Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, we use our incremental borrowing rate based on the information available at the lease commencement date. (in thousands) Classification on the Balance Sheet December 31, 2020 Assets Operating lease assets Operating lease assets $ 8,026 Total lease assets $ 8,026 Liabilities Current Operating Other current liabilities $ 988 Non-current Operating Operating lease liabilities 7,865 Total lease liabilities $ 8,853 Lease Term and Discount Rate December 31, 2020 Weighted-average remaining lease term (years) Operating leases 6.6 Weighted-average discount rate Operating leases 8.0 %
Summary of Information Related to Lease Costs for Operating Leases	The table below presents information related to the lease costs for operating leases (in thousands): Year Ended December 31, (in thousands) Classification 2020 2019 2018 Operating lease costs (a) Research and development $ 955 $ 609 $ 298 General and administrative 1,191 368 83 Total operating lease costs $ 2,146 $ 977 $ 381 (a) Includes variable lease costs which are immaterial
Reconciliation of Undiscounted Cash Flow to Operating Lease Liabilities	The table below reconciles the undiscounted cash flow for each of the first five years and total of the remaining years to the operating lease liabilities recorded on the balance sheet as of December 31, 2020 (in thousands): Operating leases Years ending December 31, 2021 1,657 2022 1,703 2023 1,634 2024 1,679 2025 1,725 Thereafter 3,131 Total future minimum lease payments $ 11,529 Less: present value adjustment (2,676 ) Total operating lease liabilities $ 8,853

Loan Payable (Tables)

Loan Payable (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Outstanding Debt Obligations	As of December 31, 2020 the future principal payments due under the Loan Agreement, excluding interest, are as follows: Amount 2021 — 2022 4,631 2023 9,972 2024 5,397 Total principal outstanding 20,000 End of term charge 395 Unamortized debt issuance costs (502 ) Total 19,893

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Summary of Common Stock Shares Reserved for Future Issuance	The Company has reserved authorized shares of common stock for future issuance at December 31, 2020 and December 31, 2019 as follows: December 31, 2020 December 31, 2019 Common stock options outstanding 6,644,780 5,744,036 Options available for grant under Equity Incentive Plans 932,051 938,738 7,576,831 6,682,774

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Summary of Stock Option Activity	Stock option activity during 2020 is as follows: Weighted average Weighted Remaining average contractual Aggregate Options exercise for intrinsic outstanding price life (Years) value (in thousands) Balance as of December 31, 2019 5,744,036 $ 16.88 7.5 $ 72,251 Cancelled (635,797 ) $ 30.94 Granted 2,039,037 $ 18.32 Exercised (502,496 ) $ 4.59 Balance as of December 31, 2020 6,644,780 $ 16.91 7.3 $ 35,464 Exercisable at December 31, 2020 3,542,190 $ 12.94 6.0 $ 31,686 Vested at December 31, 2020 and expected to vest 6,644,780 $ 16.91 7.3 $ 35,464
Employee and Non-employee Stock Options
Summary of Share-Based Compensation Expense Included in Statements of Operations	Total share-based compensation expense included in the statements of operations is as follows: Year Ended December 31, 2020 2019 2018 in thousands Research and development $ 6,902 $ 6,261 $ 5,218 General and administrative 11,868 10,188 5,007 Total stock-based compensation expense $ 18,770 $ 16,449 $ 10,225
Summary of Fair Value of Stock Options Granted Using Black-Scholes Options Pricing Model	The fair value of each option grant is estimated on the grant date using the Black-Scholes option-pricing model, using the following weighted average assumptions: Year Ended December 31, 2020 2019 2018 Expected volatility 74.8 - 81.0% 74.2 - 82.1% 74.9 - 86.5% Weighted-average risk free rate 0.3-1.7% 1.4 - 2.6% 2.3 - 3.0% Dividend yield —% —% —% Expected term (in years) 6.02 6.02 6.04 Weighted-average grant-date fair value per share $ 12.17 $ 14.94 $ 26.42

Net Loss Per Common Share (Tabl

Net Loss Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Potentially Dilutive Securities Excluded from Computations of Diluted Weighted-average Shares Outstanding	For the years ended December 31, 2020, 2019 and 2018, the following potentially dilutive securities have been excluded from the computations of diluted weighted-average shares outstanding because the effect would be anti-dilutive: Year Ended December 31, 2020 2019 2018 Stock options issued and outstanding 6,576,688 5,443,730 4,318,731 6,576,688 5,443,730 4,318,731

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Components of Income Tax Expense (Benefit) Attributable to Continuing Operations	The components of income tax expense (benefit) attributable to continuing operations are as follows: Year ended December 31, 2020 2019 2018 Current Expense: Federal $ — $ — $ — State — — — Foreign 1,410 — — 1,410 — — Deferred Expense: Federal — — — State Foreign — — — $ 1,410 $ — $ —
Summary of Differences Between the Income Tax Expense Attributable to Continuing Operations and the Expense Computed at U.S. Statutory Income Tax Rate	The differences between the company’s income tax expense attributable to continuing operations and the expense computed at the 21% U.S. statutory income tax rate were as follows (in thousands): Year ended December 31, 2020 2019 2018 Federal income tax benefit at statutory rate: $ (20,547 ) $ (25,714 ) $ (17,910 ) Increase (reduction) in income tax resulting from: State Income Taxes (1,779 ) (2,369 ) (1,518 ) Increase in Valuation Allowance 23,782 29,499 26,614 Write off Sec. 382 Limited Carryforwards — 1,858 — Stock Compensation 1,341 461 (3,011 ) Research and Development Credit (3,091 ) (3,529 ) (4,187 ) Foreign Withholding Tax 1,410 — — Other 294 (206 ) 12 $ 1,410 $ — $ —
Components of Tax Effects of Temporary Differences and Operating Loss Carryforwards Including Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities	The tax effects of temporary differences and operating loss carryforwards that gave rise to significant portions of the deferred tax assets and deferred tax liabilities were as follows at December 31, 2020 and 2019 (in thousands): Year ended December 31, 2020 2019 Deferred tax assets Accrued expenses $ 2,863 $ 2,205 Operating lease liabilities 2,034 2,348 Stock compensation 7,147 4,865 Capitalized patents and licenses - 2,156 R&D credits 13,965 10,874 Net operating loss carryforwards 85,842 65,869 Other 20 6 Deferred tax assets 111,871 88,323 Deferred tax liabilities Operating lease assets (1,844 ) (2,263 ) Other (245 ) (60 ) Deferred tax liabilities (2,089 ) (2,323 ) Valuation allowance (109,782 ) (86,000 ) Net deferred tax assets $ — $ —
Summary of Changes in the Deferred Tax Valuation Allowance	The table below summarizes changes in the deferred tax valuation allowance (in thousands): 2020 2019 2018 Balance at beginning of year $ 86,000 $ 56,501 $ 29,887 Charges to costs and expenses 25,170 31,357 26,614 Write-offs (1,388 ) (1,858 ) — Balance at end of year 109,782 86,000 56,501

Quarterly Results of Operatio_2

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations	The following table contains quarterly financial information for 2020 and 2019. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. Three Months Ended (unaudited) (in thousands, except share and per share amounts) March 31, June 30, September 30, December 31, 2020 2020 2020 2020 License Revenue $ - $ 2,140 $ 26,599 $ 16,546 Total operating expenses 31,821 32,962 36,344 40,634 Loss from operations (31,821 ) (30,822 ) (9,745 ) (24,088 ) Total other income (expense), net 798 (388 ) (998 ) (780 ) Loss before income taxes (31,023 ) (31,210 ) (10,743 ) (24,868 ) Income tax expense — — 931 479 Net loss $ (31,023 ) $ (31,210 ) $ (11,674 ) $ (25,347 ) Net loss per share, basic and diluted $ (0.82 ) $ (0.83 ) $ (0.31 ) $ (0.67 ) Weighted average common shares outstanding, basic and diluted 37,659,722 37,786,208 38,009,204 38,053,609 March 31, June 30, September 30, December 31, 2019 2019 2019 2019 License Revenue $ - $ - $ - $ - Total operating expenses 25,881 32,583 34,024 36,553 Loss from operations (25,881 ) (32,583 ) (34,024 ) (36,553 ) Total other income (expense), net 1,929 1,893 1,660 1,112 Loss before income taxes (23,952 ) (30,690 ) (32,364 ) (35,441 ) Income tax expense — — — — Net loss $ (23,952 ) $ (30,690 ) $ (32,364 ) $ (35,441 ) Net loss per share, basic and diluted $ (0.64 ) $ (0.82 ) $ (0.86 ) $ (0.94 ) Weighted average common shares outstanding, basic and diluted 37,396,980 37,470,926 37,540,380 37,586,218

Description of Business - Addit

Description of Business - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)Product	Dec. 31, 2019USD ($)
Description Of Business [Line Items]
Number of clinical-stage product candidates from pipeline | Product	2
Accumulated deficit	$ 436,107	$ 336,853
Cash and cash equivalents	$ 207,306	$ 269,208
Minimum
Description Of Business [Line Items]
Expected period to fund operations by existing cash resources	12 months
Simcere License Agreement
Description Of Business [Line Items]
Milestone payments	$ 156,000
Upfront payments along with sales based royalties	14,000
Milestone payments	156,000
EQRX License Agreement
Description Of Business [Line Items]
Milestone payments	330,000
Upfront payments along with sales based royalties	26,000
Milestone payments	$ 330,000

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 30, 2018
Summary Of Significant Accounting Policies [Line Items]
Impairment charge of long-lived assets	$ 0	$ 0	$ 0
Changes in valuation methodology	0	0
Loan payable	19,893,000
Unrecognized income tax benefits	0	0
Accrued income taxes	0	0
Patent | General and Administrative Costs
Summary Of Significant Accounting Policies [Line Items]
Legal expenses	2,761,000	$ 2,114,000	$ 1,352,000
Significant Other Unobservable Inputs (Level 3)
Summary Of Significant Accounting Policies [Line Items]
Loan payable	19,900,000
Standby Letter of Credit | Restricted Cash
Summary Of Significant Accounting Policies [Line Items]
Security deposit	$ 500,000			$ 500,000

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Property and Equipment Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2020
Computer Equipment
Property Plant And Equipment [Line Items]
Estimated useful lives	5 years
Laboratory Equipment
Property Plant And Equipment [Line Items]
Estimated useful lives	5 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Estimated useful lives	7 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Estimated useful lives	7 years

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies - Summary of Financials Instruments and Respective Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Assets at fair value	$ 206,150	$ 268,436
Money Market Funds
Assets
Assets at fair value	190,180	252,563
Certificates of Deposit
Assets
Assets at fair value	15,970	15,873
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Assets at fair value	206,150	268,436
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money Market Funds
Assets
Assets at fair value	190,180	252,563
Quoted Prices in Active Markets for Identical Assets (Level 1) | Certificates of Deposit
Assets
Assets at fair value	$ 15,970	$ 15,873

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Accumulated depreciation	$ (827)	$ (677)
Property and equipment, net	2,482	3,538
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	327	332
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	334	871
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	866	1,071
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,782	$ 1,941

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation expenses relating to property and equipment	$ 582	$ 356	$ 175

Patent License Agreement - Addi

Patent License Agreement - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended			49 Months Ended
	Dec. 31, 2016	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Patent License Agreement [Line Items]
Non-refundable license issue fee		$ 73,271	$ 89,002	$ 70,683
University
Patent License Agreement [Line Items]
License agreement date		Nov. 23, 2016
License agreement amendment date		Mar. 24, 2017
Milestone payments		$ 0			$ 600
Term of license agreement description		The term of the license agreement will continue until the later of (i) the expiration of the last valid claim within the patent rights covering the product in such country, (ii) the expiration of market exclusivity in such country and (iii) the 10th anniversary of the first commercial sale in such country. The University may terminate the agreement in the event (i) the Company fails to pay any amount or make any report when required to be made and fails to cure such failure within thirty (30) days after receipt of notice from the University, (ii) is in breach of any provision of the agreement and fails to remedy within forty-five (45) days after receipt of notice, (iii) makes a report to the University under the agreement that is determined to be materially false, (iv) declares insolvency or bankruptcy or (v) takes an action that causes patent rights or technical information to be subject to lien or encumbrance and fails to remedy any such breach with in forty-five (45) days of receipt of notice from the University. The Company may terminate the agreement at any time on written notice to the University at least ninety (90) days prior to the termination date specified in the notice. Upon expiration or termination of the agreement, all rights revert to the University.
License agreement termination notice period		90 days
University | Maximum
Patent License Agreement [Line Items]
Milestone payments		$ 2,600
University | License
Patent License Agreement [Line Items]
Non-refundable license issue fee	$ 500

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued external research	$ 3,219	$ 2,737
Accrued professional fees and other	3,920	1,487
Accrued external clinical study costs	5,683	7,996
Accrued compensation expense	3,664	3,183
Accrued expenses	$ 16,486	$ 15,403

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands	Mar. 20, 2020	Jan. 27, 2016	Jan. 10, 2014	Nov. 30, 2018USD ($)ft²	Dec. 31, 2020USD ($)
Operating Leased Assets [Line Items]
Lease expiration date	May 31, 2020	Dec. 31, 2022	Jul. 31, 2017	Sep. 30, 2027
Renewal term		5 years		5 years
Laboratory and office space lease to secure | ft²				60,000
Lease commencement date				Sep. 2, 2019
Cash payments for measurement of operating leases					$ 1,683
Standby Letter of Credit | Restricted Cash
Operating Leased Assets [Line Items]
Security deposit				$ 500	$ 500

Leases - Summary of Lease Posit

Leases - Summary of Lease Position and Weighted-Average Lease Term and Discount Rate of Operating Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Operating lease assets	$ 8,026	$ 9,853
Total lease assets	8,026
Liabilities
Current operating lease liabilities	$ 988
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent
Non-current operating lease liabilities	$ 7,865	$ 9,535
Total lease liabilities	$ 8,853
Weighted-average remaining lease term (years)
Operating leases	6 years 7 months 6 days
Weighted-average discount rate
Operating leases	8.00%

Leases - Summary of Information

Leases - Summary of Information Related to Lease Costs for Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Leased Assets [Line Items]
Total operating lease costs	$ 2,146	$ 977	$ 381
Research and Development
Operating Leased Assets [Line Items]
Operating lease costs	955	609	298
General and Administrative
Operating Leased Assets [Line Items]
Operating lease costs	$ 1,191	$ 368	$ 83

Leases - Reconciliation of Undi

Leases - Reconciliation of Undiscounted Cash Flow to Operating Lease Liabilities (Details) $ in Thousands	Dec. 31, 2020USD ($)
Leases [Abstract]
2021	$ 1,657
2022	1,703
2023	1,634
2024	1,679
2025	1,725
Thereafter	3,131
Total future minimum lease payments	11,529
Less: present value adjustment	(2,676)
Total operating lease liabilities	$ 8,853

Loan Payable - Additional Infor

Loan Payable - Additional Information (Details) - USD ($) $ in Thousands	May 29, 2020	Dec. 31, 2020
Debt Instrument [Line Items]
Loan amount		$ 19,893
Loan net carrying amount		$ 20,000
Loan Agreement | Hercules Capital, Inc.
Debt Instrument [Line Items]
Loan amount	$ 20,000
Earliest maturity date		Jun. 1, 2022
Latest maturity date		Jan. 1, 2023
Debt instrument maturity date description		Following the interest only period, the Company will repay the principal balance and interest of the advances in equal monthly installments through June 1, 2024.
Interest rate description		greater of either (i) (a) the prime rate as reported in The Wall Street Journal, plus (b) 6.40%, and (ii) 9.65%.
Loan agreement, basis spread on variable rate		6.40%
Loan agreement, interest rate, stated percentage		9.65%
Prepayment fee description		3.0% of the prepayment amount in the first year; (b) 2.0% of the prepayment amount in the second year; and (c) 1.0% of the prepayment amount in the third year
Percentage of prepayment of loan amount for year first		3.00%
Percentage of prepayment of loan amount for year second		2.00%
Percentage of prepayment of loan amount for year third		1.00%
Percentage of loan amount prepayment charge		6.95%
Loan agreement, issuance costs		$ 400
Line Of Credit Facility Upfront Fee		200
Loan Agreement | Hercules Capital, Inc. | First Tranche
Debt Instrument [Line Items]
Loan amount	30,000
Milestone payments	20,000
End of term fee		$ 2,100
Percentage of aggregate amount of all loan advances payment		6.95%
Loan net carrying amount		$ 19,400
Loan Agreement | Hercules Capital, Inc. | First Tranche | Other Income (Expense)
Debt Instrument [Line Items]
Interest expense, loan agreement		1,800
Loan Agreement | Hercules Capital, Inc. | Second Tranche
Debt Instrument [Line Items]
Loan amount	20,000
Loan Agreement | Hercules Capital, Inc. | Third Tranche
Debt Instrument [Line Items]
Loan amount	30,000
Loan Agreement | Hercules Capital, Inc. | Fourth Tranche
Debt Instrument [Line Items]
Loan amount	$ 20,000
Loan Agreement | Hercules Capital, Inc. | Maximum
Debt Instrument [Line Items]
Loan amount		$ 100,000

Loan Payable - Schedule Future

Loan Payable - Schedule Future Principal Payments Due Under Loan Agreement Excluding Interest (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Debt Disclosure [Abstract]
2022	$ 4,631
2023	9,972
2024	5,397
Total principal outstanding	20,000
End of term charge	395
Unamortized debt issuance costs	(502)
Loan amount	$ 19,893

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - $ / shares	May 22, 2017	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Common stock, par value		$ 0.0001	$ 0.0001
Common stock, shares authorized		120,000,000	120,000,000
Common stock, voting rights		Holders of common stock are entitled to one vote per share
Undesignated preferred stock, shares authorized to issue		5,000,000
Preferred stock, shares issued		0
Preferred stock, shares outstanding		0
IPO | Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of outstanding preferred stock to common stock	18,933,053

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Common Stock Shares Reserved for Future Issuance (Details) - shares	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Common stock, shares reserved for future issuance	7,576,831	6,682,774
Common Stock Options Outstanding
Class Of Stock [Line Items]
Common stock, shares reserved for future issuance	6,644,780	5,744,036
Options Available For Grant Under Equity Incentive Plan
Class Of Stock [Line Items]
Common stock, shares reserved for future issuance	932,051	938,738

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Jan. 01, 2019	Jan. 01, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 31, 2017	Mar. 31, 2011
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation				$ 18,770	$ 16,449	$ 10,225
Employee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options, maximum term					10 years
Stock-based compensation				18,770	$ 16,351	8,157
Unrecognized stock-based compensation costs				$ 38,834
Weighted-average recognition period				2 years 5 months 1 day
Non-employee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation				$ 0	$ 98	$ 2,068
2017 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares approved for grant under equity incentive plan							1,932,000
Number of shares available for grant under equity incentive plan				932,051
Number of additional shares approved for grant under equity incentive plan	1,096,553	1,096,553	1,066,692
2011 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares approved for grant under equity incentive plan								4,400,640
Number of shares available for grant under equity incentive plan					0

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Share-Based Compensation Expense Included in Statements of Operations (Details) - Employee and Non-employee Stock Options - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 18,770	$ 16,449	$ 10,225
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	6,902	6,261	5,218
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 11,868	$ 10,188	$ 5,007

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Stock Options Granted Using Black-Scholes Options Pricing Model (Details) - Employee and Non-employee Stock Options - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	74.80%	74.20%	74.90%
Expected volatility, maximum	81.00%	82.10%	86.50%
Weighted-average risk free rate, minimum	0.30%	1.40%	2.30%
Weighted-average risk free rate, maximum	1.70%	2.60%	3.00%
Expected term (in years)	6 years 7 days	6 years 7 days	6 years 14 days
Weighted-average grant-date fair value per share	$ 12.17	$ 14.94	$ 26.42

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Options outstanding
Beginning balance	5,744,036
Cancelled	(635,797)
Granted	2,039,037
Exercised	(502,496)
Ending balance	6,644,780	5,744,036
Exercisable	3,542,190
Vested and expected to vest	6,644,780
Weighted average exercise price
Beginning balance	$ 16.88
Cancelled	30.94
Granted	18.32
Exercised	4.59
Ending balance	16.91	$ 16.88
Exercisable	12.94
Vested and expected to vest	$ 16.91
Weighted average, Remaining contractual for life (Years)
Balance	7 years 3 months 19 days	7 years 6 months
Exercisable	6 years
Vested and expected to vest	7 years 3 months 19 days
Weighted average, Aggregate intrinsic value
Balance	$ 35,464	$ 72,251
Exercisable	31,686
Vested and expected to vest	$ 35,464

License Revenue - Additional In

License Revenue - Additional Information (Details) - USD ($) $ in Thousands	Aug. 03, 2020	Jul. 22, 2020	May 22, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2020	Jun. 15, 2020
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License revenue recognized				$ 16,546	$ 26,599	$ 2,140		$ 45,285
ARC Therapeutics, LLC
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Upfront payment received			$ 1,000
Percentage of equity interest received as consideration			10.00%
Value of equity interest received			$ 1,100
Milestone payments receivable			2,000
License revenue recognized			$ 2,100					2,100
Equity interest			10.00%
Genor Biopharma Co. Inc.
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Milestone payments receivable									$ 40,000
License revenue recognized				600			$ 6,000
Non-refundable, upfront payment									6,000
Amount owed upon the delivery of existing inventory									$ 600
EQRx Inc.
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Upfront payment received		$ 20,000
Milestone payments receivable		290,000
License revenue recognized				$ 700			20,000
Non-refundable, upfront payment		20,000
Amount owed upon the delivery of existing inventory		$ 700
Typical payment terms on invoice payment		30 days
Number of days due from invoice date		30 days
EQRx Inc. | Reimbursement of costs
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Upfront payment received								200
Reimbursement of costs associated revenue								1,300
Remaining amount recognized not invoiced								1,100
Nanjing Simcere Dongyuan Pharmaceutical Co., Ltd
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Upfront payment received	$ 14,000						$ 14,000
Milestone payments receivable	156,000
License revenue recognized								$ 14,000
Non-refundable, upfront payment	14,000
Withholding taxes	$ 1,400

Net Loss Per Common Share (Deta

Net Loss Per Common Share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding	6,576,688	5,443,730	4,318,731
Stock Options Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding	6,576,688	5,443,730	4,318,731

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Unrecognized income tax benefits		$ 0	$ 0
Unrecognized income tax benefits impact on effective income tax rate		0	0
Accrued income taxes		$ 0	$ 0
U.S. statutory income tax rate		21.00%	21.00%	21.00%
Valuation allowance		$ 109,782,000	$ 86,000,000
Federal research and development credit carryforwards		13,965,000	$ 10,874,000
Federal
Income Taxes [Line Items]
Net operating loss carryforwards		$ 373,100,000
Net operating loss carryforwards expiration year		2029
Net operating loss carryforwards expire in 2029		$ 95,400,000
Net operating loss carryforwards indefinite expiration period		277,600,000
Federal research and development credit carryforwards		14,000,000
Operating loss carryforwards limitation	$ 8,000,000
State
Income Taxes [Line Items]
Net operating loss carryforwards		$ 379,800,000
Net operating loss carryforwards expiration year		2024
Operating loss carryforwards limitation	1,200,000
Research and Development (R&D) Credit Carryforwards
Income Taxes [Line Items]
Tax credit carryforwards limitation	$ 100,000
Research and Development (R&D) Credit Carryforwards | Federal
Income Taxes [Line Items]
Expiration year for tax credit carryforwards		2035

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Benefit) Attributable to Continuing Operations (Details)	12 Months Ended
	Dec. 31, 2020USD ($)
Current Expense:
Foreign	$ 1,410
Total current expense	1,410
Deferred Expense:
Total deferred expense	$ 1,410

Income Taxes - Summary of Diffe

Income Taxes - Summary of Differences Between the Income Tax Expense Attributable to Continuing Operations and the Expense Computed at U.S. Statutory Income Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal income tax benefit at statutory rate:			$ (20,547)	$ (25,714)	$ (17,910)
Increase (reduction) in income tax resulting from:
State Income Taxes			(1,779)	(2,369)	(1,518)
Increase in Valuation Allowance			23,782	29,499	26,614
Write off Sec. 382 Limited Carryforwards				1,858
Stock Compensation			1,341	461	(3,011)
Research and Development Credit			(3,091)	(3,529)	(4,187)
Foreign Withholding Tax			1,410
Other			294	$ (206)	$ 12
Income tax expense (benefit)	$ 479	$ 931	$ 1,410

Income Taxes - Components of Ta

Income Taxes - Components of Tax Effects of Temporary Differences and Operating Loss Carryforwards Including Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets
Accrued expenses	$ 2,863	$ 2,205
Operating lease liabilities	2,034	2,348
Stock compensation	7,147	4,865
Capitalized patents and licenses		2,156
R&D credits	13,965	10,874
Net operating loss carryforwards	85,842	65,869
Other	20	6
Deferred tax assets	111,871	88,323
Deferred tax liabilities
Operating lease assets	(1,844)	(2,263)
Other	(245)	(60)
Deferred tax liabilities	(2,089)	(2,323)
Valuation allowance	$ (109,782)	$ (86,000)

Income Taxes - Summary of Chang

Income Taxes - Summary of Changes in the Deferred Tax Valuation Allowance (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation Allowance [Line Items]
Balance at beginning of year	$ 86,000	$ 56,501	$ 29,887
Charges to costs and expenses	25,170	31,357	26,614
Write-offs	(1,388)	(1,858)
Balance at end of year	$ 109,782	$ 86,000	$ 56,501

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)	May 22, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
License revenue recognized		$ 16,546,000	$ 26,599,000	$ 2,140,000	$ 45,285,000
ARC License Agreement
Related Party Transaction [Line Items]
License revenue recognized	$ 2,100,000				2,100,000
Scientific Advisory | Member of Board of Directors
Related Party Transaction [Line Items]
Consulting fees					6,000	$ 6,000	$ 6,000
Senior Advisor Agreement
Related Party Transaction [Line Items]
Service Payment					$ 200,000
Senior Advisor Agreement | Member of Board of Directors
Related Party Transaction [Line Items]
Senior advisor agreement expiration date					Dec. 31, 2023
Service Payment					$ 60,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended
	Feb. 09, 2021	Feb. 23, 2021	Dec. 31, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Common stock, shares authorized			120,000,000	120,000,000
Subsequent Event | Inducement Plan [Member]
Subsequent Event [Line Items]
Reserved shares of common stock		500,000
Subsequent Event | At The Market Offerings
Subsequent Event [Line Items]
Common stock, shares authorized	3,513,027
Net proceeds from issuance of common stock	$ 86.4

Quarterly Financial Information

Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
License revenue	$ 16,546	$ 26,599	$ 2,140						$ 45,285
Total operating expenses	40,634	36,344	32,962	$ 31,821	$ 36,553	$ 34,024	$ 32,583	$ 25,881	141,761	$ 129,041	$ 89,286
Loss from operations	(24,088)	(9,745)	(30,822)	(31,821)	(36,553)	(34,024)	(32,583)	(25,881)	(96,476)	(129,041)	(89,286)
Total other income (expense), net	(780)	(998)	(388)	798	1,112	1,660	1,893	1,929	(1,368)	6,594	3,998
Loss before income taxes	(24,868)	(10,743)	(31,210)	(31,023)	(35,441)	(32,364)	(30,690)	(23,952)	(97,844)	(122,447)	(85,288)
Income tax expense	479	931							1,410
Net loss	$ (25,347)	$ (11,674)	$ (31,210)	$ (31,023)	$ (35,441)	$ (32,364)	$ (30,690)	$ (23,952)	$ (99,254)	$ (122,447)	$ (85,288)
Net loss per share, basic and diluted	$ (0.67)	$ (0.31)	$ (0.83)	$ (0.82)	$ (0.94)	$ (0.86)	$ (0.82)	$ (0.64)	$ (2.62)	$ (3.27)	$ (2.56)
Weighted average common shares outstanding, basic and diluted	38,053,609	38,009,204	37,786,208	37,659,722	37,586,218	37,540,380	37,470,926	37,396,980	37,878,026	37,499,256	33,316,719