Day One Biopharmaceuticals (DAWN) 10-Q 10 Aug 21 2021 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2021	Jul. 31, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Registrant Name	DAY ONE BIOPHARMACEUTICALS, INC.
Entity Central Index Key	0001845337
Entity File Number	001-40431
Entity Tax Identification Number	83-2415215
Entity Incorporation, State or Country Code	DE
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	No
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Address, Address Line One	395 Oyster Point Blvd.
Entity Address, Address Line Two	Suite 217
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	484-0899
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	DAWN
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		61,928,939

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 309,996	$ 43,728
Prepaid expenses and other current assets	6,029	1,343
Total current assets	316,025	45,071
Property and equipment, net	67	77
Operating lease right-of-use asset	319	406
Deposits and other long-term assets	126	107
Total assets	316,537	45,661
Current liabilities:
Accounts payable	348	202
Accrued expenses and other current liabilities	4,113	1,596
Current portion of operating lease liabilities	201	198
Total current liabilities	4,662	1,996
Operating lease liabilities, long-term	112	204
Total liabilities	4,774	2,200
Commitments and contingencies (Note 8)
Redeemable convertible preferred shares, no par value; no shares authorized, issued and outstanding at June 30, 2021; 22,851,257 shares authorized, issued and outstanding at December 31, 2020		91,964
Redeemable convertible noncontrolling interest		5,702
Stockholders' equity/members' (deficit)
Preferred stock, 10,000,000 shares authorized, $0.0001 par value, no shares issued and outstanding at June 30, 2021; No shares authorized, issued, and outstanding at December 31, 2020
Additional paid-in-capital	398,065
Incentive shares, no par value; no shares authorized, issued and outstanding at June 30, 2021; 4,312,540 shares authorized and 4,112,012 shares issued and outstanding at December 31, 2020		637
Accumulated deficit	(86,308)	(56,842)
Total stockholders' equity/members' (deficit)	311,763	(54,205)
Total liabilities, redeemable convertible preferred shares, redeemable convertible noncontrolling interest and members' deficit	316,537	45,661
Common Class A [Member]
Stockholders' equity/members' (deficit)
Common Stock, Value, Issued		$ 2,000
Common Class B [Member]
Stockholders' equity/members' (deficit)
Common Stock, Value, Issued	$ 6

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Preferred Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Preferred Stock, Shares Authorized	10,000,000	0
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Shares Authorized	500,000,000
Common Stock, Shares Issued	61,928,939	6,035,869
Common Stock, Shares Outstanding	61,928,939	6,035,869
Deferred Shares Par Value Per Shares	$ 0	$ 0
Deferred Compensation Arrangement with Individual, Shares Authorized for Issuance	0	4,312,540
Deferred Compensation Arrangement with Individual, Shares Issued	0	4,112,012
Deferred Shares Outstanding	0	4,112,012
Redeemable Convertible Preferred Stock [Member]
Temporary Equity, Par or Stated Value Per Share	$ 0	$ 0
Temporary Equity, Shares Authorized	0	22,851,257
Temporary Equity, Shares Issued	0	22,851,257
Temporary Equity, Shares Outstanding	0	22,851,257
Common Class A [Member]
Common Stock, Par or Stated Value Per Share	$ 0	$ 0
Common Stock, Shares Authorized	0	28,887,127
Common Stock, Shares Issued	0	6,035,869
Common Stock, Shares Outstanding	0	6,035,869
Common Class B [Member]
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	500,000,000	0
Common Stock, Shares Issued	61,928,939	0
Common Stock, Shares Outstanding	61,928,939	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating expenses:
Research and development	$ 9,914	$ 1,437	$ 22,547	$ 2,398
General and administrative	5,525	872	8,990	1,682
Total operating expenses	15,439	2,309	31,537	4,080
Loss from operations	(15,439)	(2,309)	(31,537)	(4,080)
Interest expense	(7)	(10)	(14)	(13)
Other expense	(27)		(24)
Changes in fair value of derivative tranche liability		(90)		(308)
Net loss and comprehensive loss	(15,473)	(2,409)	(31,575)	(4,401)
Net loss attributable to redeemable convertible noncontrolling interests	(1,191)	(649)	(2,109)	(1,106)
Exchange of redeemable noncontrolling interest shares – deemed dividend	(99,994)		(99,994)
Net loss attributable to common share members/common stockholders	$ (114,276)	$ (1,760)	$ (129,460)	$ (3,295)
Net loss per share, basic and diluted	$ (5.04)	$ (0.32)	$ (10.81)	$ (0.61)
Weighted-average number of common shares used in computing net loss per share, basic and diluted	22,661,889	5,456,203	11,976,577	5,383,549

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Redeemable Convertible Preferred Shares, Redeemable Noncontrolling Interest and Stockholders' Equity/ Members' (Deficit) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock [Member]	Redeemable Noncontrolling Interest [Member]	Common Stock [Member]	Common Shares [Member]	Incentive Shares [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2019	$ (10,673)	$ 30,504	$ 5,487	$ 2,000		$ 111	$ 0	$ (12,784)
Beginning Balance (In shares) at Dec. 31, 2019		12,502,752		6,035,869		1,488,421
Issuance of incentive shares						528,211
Cancellations of incentive shares						(477,582)
Share-based compensation expenses	59					$ 59
Net loss attributable to redeemable convertible noncontrolling interests			(457)
Net loss attributable to Day One Biopharmaceuticals Holding Company, LLC members	(1,535)							(1,535)
Ending Balance at Mar. 31, 2020	(12,149)	$ 30,504	5,030	$ 2,000		$ 170	0	(14,319)
Ending Balance (In shares) at Mar. 31, 2020		12,502,752		6,035,869		1,539,050
Beginning Balance at Dec. 31, 2019	(10,673)	$ 30,504	5,487	$ 2,000		$ 111	0	(12,784)
Beginning Balance (In shares) at Dec. 31, 2019		12,502,752		6,035,869		1,488,421
Net loss attributable to redeemable convertible noncontrolling interests	1,106
Ending Balance at Jun. 30, 2020	(13,852)	$ 30,504	4,381	$ 2,000		$ 227	0	(16,079)
Ending Balance (In shares) at Jun. 30, 2020		12,502,752		6,035,869		1,560,469
Beginning Balance at Mar. 31, 2020	(12,149)	$ 30,504	5,030	$ 2,000		$ 170	0	(14,319)
Beginning Balance (In shares) at Mar. 31, 2020		12,502,752		6,035,869		1,539,050
Issuance of incentive shares						21,419
Share-based compensation expenses	57					$ 57
Net loss attributable to redeemable convertible noncontrolling interests	649		(649)
Net loss attributable to common members/ stockholders	(1,760)							(1,760)
Ending Balance at Jun. 30, 2020	(13,852)	$ 30,504	4,381	$ 2,000		$ 227	0	(16,079)
Ending Balance (In shares) at Jun. 30, 2020		12,502,752		6,035,869		1,560,469
Beginning Balance at Dec. 31, 2020	(54,205)	$ 91,964	5,702	$ 0	$ 2,000	$ 637	0	(56,842)
Beginning Balance (In shares) at Dec. 31, 2020		22,851,257		0	6,035,869	4,112,012
Issuance of incentive shares						874,335
Share-based compensation expenses	538					$ 538
Issuance of Series B redeemable convertible preferred shares for cash, net of issuance costs		$ 129,757
Issuance of Series B redeemable convertible preferred shares for cash, net of issuance costs (In shares)		9,638,141
Net loss attributable to redeemable convertible noncontrolling interests			(919)
Net loss attributable to Day One Biopharmaceuticals Holding Company, LLC members	(15,182)							(15,182)
Ending Balance at Mar. 31, 2021	(68,849)	$ 221,721	4,783	$ 0	$ 2,000	$ 1,175	0	(72,024)
Ending Balance (In shares) at Mar. 31, 2021		32,489,398		0	6,035,869	4,986,352
Beginning Balance at Dec. 31, 2020	(54,205)	$ 91,964	5,702	$ 0	$ 2,000	$ 637	0	(56,842)
Beginning Balance (In shares) at Dec. 31, 2020		22,851,257		0	6,035,869	4,112,012
Net loss attributable to redeemable convertible noncontrolling interests	2,109
Ending Balance at Jun. 30, 2021	311,763	$ 0	0	$ 6	$ 0	$ 0	398,065	(86,308)
Ending Balance (In shares) at Jun. 30, 2021		0		61,928,939	0	0
Beginning Balance at Mar. 31, 2021	(68,849)	$ 221,721	4,783	$ 0	$ 2,000	$ 1,175	0	(72,024)
Beginning Balance (In shares) at Mar. 31, 2021		32,489,398		0	6,035,869	4,986,352
Issuance of incentive shares						2,085,460
Cancellations of incentive shares						(265,596)
Share-based compensation expenses	2,537						2,537
Net loss attributable to redeemable convertible noncontrolling interests	1,191
Conversion of redeemable convertible preferred, common, and incentive shares into common stock , Value	221,721	$ (221,721)		$ 4	$ (2,000)	$ (1,175)	224,892
Conversion of redeemable convertible preferred, common, and incentive shares into common stock (In shares)		(32,489,398)		43,958,557	(6,035,869)	(6,806,216)
Conversion of redeemable noncontrolling interest to common stock	3,592		(3,592)	$ 1			3,592
Conversion of redeemable noncontrolling interest to common stock (In shares)				6,470,382
Net loss attributable to Day One Biopharmaceuticals Holding Company, LLC members			(1,191)
Common stock issued in IPO, net of issuance costs of $16,995	167,045			$ 1			167,044
Common stock issued in IPO, net of issuance costs of $16,995 (In shares)				11,500,000
Net loss attributable to common members/ stockholders	(14,284)							(14,284)
Ending Balance at Jun. 30, 2021	$ 311,763	$ 0	$ 0	$ 6	$ 0	$ 0	$ 398,065	$ (86,308)
Ending Balance (In shares) at Jun. 30, 2021		0		61,928,939	0	0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Redeemable Convertible Preferred Shares, Redeemable Noncontrolling Interest and Stockholders' Equity/ Members' (Deficit) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021
Common Stock [Member]
Stock issuance costs	$ 16,995
Series B redeemable convertible preferred shares [Member]
Stock issuance costs		$ 243

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net loss	$ (31,575)	$ (4,401)
Adjustments to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development assets	8,000
Share-based compensation expense	3,075	116
Depreciation and amortization expense	10	5
Amortization of operating right-of-use assets	88	55
Non-cash interest expense	14	13
Changes in derivative tranche liabilities		308
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(4,722)	(206)
Deposits and other long-term assets	(19)	(71)
Accounts payable	145	155
Accrued expenses and other current liabilities	1,937	126
Operating lease liabilities	(102)	(73)
Net cash used in operating activities	(23,149)	(3,973)
Cash flows from investing activities
Purchases of property and equipment		(93)
Cash paid for acquired in-process research and development assets	(8,000)
Cash used in investing activities	(8,000)	(93)
Cash flows from financing activities
Proceeds from issuance of Series B redeemable convertible preferred shares, net of issuance costs	129,757
Proceeds from issuance of common stock, net	167,660
Net cash provided by financing activities	297,417
Net increase (decrease) in cash and cash equivalents	266,268	(4,066)
Cash and cash equivalents, beginning of period	43,728	27,332
Cash and cash equivalents, end of period	309,996	23,266
Supplemental disclosures of noncash activities
Exchange of 45,331,483 preferred, common, and incentive shares in connection with the Conversion (Note 1)	224,892
Exchange of redeemable convertible noncontrolling interest to 6,470,382 shares of common stock (Note 13)	3,592
Deferred offering costs not yet paid	$ 615
Right of use asset capitalization		$ 545

Description of Business, Organi

Description of Business, Organization and Liquidity	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business, Organization and Liquidity	1. DESCRIPTION OF BUSINESS, ORGANIZATION AND LIQUIDITY Organization and Business Day One Biopharmaceuticals, Inc. (the “Company”), a successor to Day One Biopharmaceuticals Holding Company, LLC (“Day One Holding LLC), is a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for patients of all ages with genetically defined cancers. The Company’s lead product candidate, DAY101, has the potential to be a first-in-class, pan-RAF The Company started its operations in November 2018 under the name Hero Therapeutics Holding Company, LLC, a limited liability company under the laws of the State of Delaware. Subsequently, it changed its name to Day One Therapeutics Holding Company, LLC in December 2018 and to Day One Biopharmaceuticals Holding Company, LLC in March 2020. On May 26, 2021, the Company completed the conversion by filing a certificate of conversion with the Secretary of State of the State of Delaware and changed its name to Day One Biopharmaceuticals, Inc. As of June 30, 2021, the Company has two wholly owned subsidiaries: DOT Therapeutics-2, Therapeutics-1, Initial Public Offering, Corporate Conversion and Exchange of Takeda’s shares On June 1, 2021, the Company closed its initial public offering (the “IPO”) in which it sold an aggregate of 11,500,000 shares of common stock at a price to the public of $16.00 per share, which included 1,500,000 shares issued upon the full exercise by the underwriters of their option to purchase additional shares of common stock. The Company received aggregate net proceeds from the IPO of $167.0 million, after deducting underwriting discounts and commissions and offering costs, of $17.0 million. The common stock began trading on the Nasdaq Global Select Market on May 27, 2021, under the symbol “DAWN”. In contemplation of the IPO, on May 26, 2021, the Company completed the conversion (the “Conversion”), which included the following: Day One Holding LLC, converted from a Delaware limited liability company to a Delaware corporation by filing a certificate of conversion with the Secretary of State of the State of Delaware; and changed its name to Day One Biopharmaceuticals, Inc. As part of the Conversion: • holders of Series A redeemable convertible preferred shares of Day One Holding LLC received one share of Series A redeemable convertible preferred stock of the Company for each Series A redeemable convertible preferred share held immediately prior to the Conversion; • holders of Series B redeemable convertible preferred shares of Day One Holding LLC received one share of Series B redeemable convertible preferred stock of the Company for each Series B redeemable convertible preferred share held immediately prior to the Conversion; • holders of common shares of Day One Holding LLC received one share of common stock of the Company for each common share held immediately prior to the Conversion; • each outstanding incentive share in Day One Holding LLC converted into a number of shares of common stock of the Company based upon a conversion price determined by the board of directors. The conversion price was determined as a difference between the IPO price of $16.00 per share and the In connection with the IPO and the Conversion, pursuant to the terms of the Millennium Stock Exchange Agreement and the Plan of Conversion, (“The Millennium Stock Exchange Agreement”) Millennium Pharmaceuticals, Inc. (“Takeda”) exchanged the 9,857,143 shares of Series A redeemable convertible preferred stock of DOT -1, Company (the “Exchange”). The Company continues to hold all property and assets of Day One Holding LLC and assumes all of the debts and obligations of Day One Holding LLC. Effective on the date of the Conversion, the member of the board of directors and officers of Day One Holding LLC became the member of the board of directors and officers of the Company. The Conversion was a tax-free par value per share. Upon the closing of the IPO, 32,489,398 shares of redeemable convertible preferred stock issued by the Company in the Conversion converted into an equal number of shares of common stock. The Company also granted options for 4,418,874 common stock shares at $16.00 per share upon the IPO date. Shares Split On May 23, 2021, Day One Holding LLC Board approved an amendment the Operating Agreement to effect a forward split of the Company’s shares at a 2.325-for-1 ratio (the “Stock Split”). The Stock Split became effective on May 23, 2021, upon approval by the members and execution of the amended LLC operating agreement. All issued and outstanding common shares, redeemable convertible preferred shares, incentive shares and per share amounts contained in these condensed consolidated financial statements have been retroactively adjusted to reflect this Stock Split for all periods presented. Liquidity The Company has incurred significant operating losses since inception and has relied primarily on public and private equity to fund its operations. On June 30, 2021, the Company had an accumulated stockholders equity/members’ (deficit) of $86.3 million. The Company expects to continue to incur substantial losses, and its ability to achieve and sustain profitability will depend on the successful development, approval, and commercialization of product candidates and on the achievement of sufficient revenues to support its cost structure. The Company may never achieve profitability, and until then, the Company will need to continue to raise additional capital. As of June 30, 2021, the Company had cash and cash equivalents of $ million. Based on current plans, the Company believes this will be sufficient to enable funding operations into 2023. Future requirements will depend on many factors and may prove to be wrong as available capital resources could be exhausted sooner than expected. Risks and Uncertainties Related to COVID-19 We are subject to risks related to public health crises such as the global pandemic associated with COVID-19. COVID-19, COVID-19 pre-pandemic COVID-19 Any outbreak of contagious diseases, or other adverse public health developments, could have a material and adverse effect on our business operations. These could include disruptions or restrictions on our ability to travel, pursue partnerships and other business transactions, receive shipments of biologic materials, as well as be impacted by the temporary closure of the facilities of suppliers. The spread of an infectious disease, including COVID-19, 10-Q, COVID-19 COVID-19 COVID-19,

Summary Of Significant Account

Summary Of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Significant Accounting Policies	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES There have been no changes to the significant accounting policies as disclosed in Note 2 to the Company’s annual consolidated financial statements for the years ended December 31, 2020 and 2019 included in the Company’s final prospectus for its IPO filed pursuant to Rule 424(b)(4) under the Securities Act with the SEC on May 27, 2021, except as noted below. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), and follow the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain notes and other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of the Company’s financial information. The condensed consolidated balance sheet as of December 31, 2020 has been derived from audited consolidated financial statements as of that date but does not include all of the financial information required by U.S. GAAP for complete financial statements. Operating results for the six months ended June 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”) . Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to, the fair value of the redeemable convertible preferred shares, the fair value of the common shares, the fair value of the derivative tranche liability, the valuation of share-based awards, the valuation of deferred tax assets and income tax uncertainties, and accruals for research and development activities. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable. Actual results may differ from those estimates or assumptions. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. As of June 30, 2021, cash equivalents include investments in money market funds. As of December 31, 2020, the Company did not have any cash equivalents and cash was held in checking accounts. Deferred Finance Issuance Costs Deferred finance issuance costs, consisting of legal, accounting, audit and filing fees relating to in-process Share/Stock-Based Compensation Prior to the IPO, the Company recognized share-based compensation expense based on the estimated fair value of all share-based awards, incentive shares and restricted common share shares, on the date of grant using the option-pricing model. The option-pricing model requires the input of subjective assumptions, including the fair value of the underlying common shares, the expected term of the award, the expected volatility, risk-free interest rates, and the dividend yield. In determining the fair value of common shares, the methodologies used to estimate the enterprise value were performed using methodologies, approaches, and assumptions consistent with the American Institute of Certified Public Accountants Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation dividend. Subsequent to closing of the IPO, the Company uses the Black-Scholes valuation model to estimate the fair value of options granted to employees and non-employees, The Black-Scholes option-pricing model, used to estimate fair value of stock options awards, requires the use of the following assumptions: • Fair Value of Common Stock • Expected Term • Expected Volatility • Risk-Free Interest Rate grant for zero-coupon U.S. Treasury • Expected Dividend Yield The Company uses the straight-line attribution method for recognizing share/stock-based compensation expense. The Company recognizes forfeitures by reducing the expense in the same period the forfeitures occur. The Company recognizes share/stock-based compensation expense for awards with performance conditions when it is probable that the condition will be met, and the award will vest. The Company classifies share/stock-based compensation expense in the Consolidated Statement of Operations and Comprehensive Loss in the same manner in which the award recipients’ payroll costs are classified or in which the award recipients’ service payments are classified. Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326). 2016-13 2016-13 2019-04, 2016-13 In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes 2019-12”), 2019-12 2019-12 In August 2020, the FASB issued ASU No. 2020-06 (“ASU 2020-06”) Debt—Debt with Conversion and Other Options (Subtopic 470-20) 815-40): 2020-06 will paid-in 2020-06 also

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. FAIR VALUE MEASUREMENTS The financial instruments of the Company measured at fair value on a recurring basis are included in cash and cash equivalents. U.S. government money market funds were valued by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy . Financial Assets and Liabilities Measured on a Recurring Basis The following table sets forth the Company’s financial instruments as of June 30, 2021 and December 31, 2020, which are measured at fair value on a recurring basis by level within the fair value hierarchy. These are classified based on the lowest level of input that is significant to the fair value measurement (in thousands): June 30, 2021 Total Level 1 Level 2 Level 3 Money market funds, included in cash and cash equivalents $ 136,876 $ 136,876 $ — $ — As of December 31, 2020, the Company did t have any money market funds. There were no transfers between Level 1, Level 2 or Level 3 categories in the six months ended June 30, 2021 or 2020.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	6 Months Ended
	Jun. 30, 2021
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid Expenses and Other Current Asset	4. PREPAID EXPENSES AND OTHER CURRENT ASSETS Prepaid and other current assets consisted of the following (in thousands): June 30, December 31, Prepaid insurance $ 4,578 $ 41 Prepaid research and development expenses 1,277 1,259 Other prepaid expenses and other assets 174 43 Total prepaid expenses and other current assets $ 6,029 $ 1,343

Property and Equipment, Net

Property and Equipment, Net	6 Months Ended
	Jun. 30, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	5. PROPERTY AND EQUIPMENT, NET Property and equipment, net, consisted of the following (in thousands): June 30, December 31, Furniture and fixtures $ 78 $ 78 Leasehold improvements 15 15 Less: accumulated depreciation and amortization (26 ) (16 ) Property and equipment, net $ 67 $ 77 Depreciation and amortization expense was immaterial for the three and six months ended June 30, 2021 and 2020.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	6 Months Ended
	Jun. 30, 2021
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accrued expenses and other current liabilities consisted of the following (in thousands): June 30, December 31, Accrued research and development expenses $ 1,642 $ 554 Accrued professional service expenses 913 298 Accrued payroll related expenses 849 717 Accrued issuance costs 615 — Other 94 27 Total accrued expenses and other current liabilities $ 4,113 $ 1,596

Significant Agreements

Significant Agreements	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Significant Agreements	7. SIGNIFICANT AGREEMENTS License agreement with Merck KGaA, Darmstadt, Germany On February 10, 2021, DOT-2, the Company’s subsidiary, entered into a license agreement (the MRKDG License Agreement), with Merck KGaA, Darmstadt, Germany, a pharmaceutical corporation located in Darmstadt, Germany. Under the MRKDG License Agreement, Merck KGaA, Darmstadt, Germany granted to the Company an exclusive worldwide license, with the right to grant sublicenses through multiple tiers, under specified patent rights and know-how non-exclusive Under the MRKDG License Agreement, the Company has obligations to use commercially reasonable efforts to develop and commercialize at least two licensed products in at least two specified major market countries by the year 2029. In consideration for the rights granted under the MRKDG License Agreement and clinical supplies, the Company made an upfront payment of $8.0 million, which was recorded as research and development expenses, as the technology does not have an alternative future use and supplies are used for research activities. The Company may also be required to make additional payments of up to $ million based upon the achievement of specified development, regulatory, and commercial milestones, as well a high, single-digit royalty percentage on future net sales of licensed products, if any. Milestones and royalties are contingent upon future events and will be recorded when the milestones are achieved and when payments are due. No milestones were achieved and due as of June 30, 2021. The term of the MRKDG License Agreement will expire on a licensed product-by-licensed country-by-country Takeda Assets Purchase Agreement On December 16, 2019, DOT-1 DOT-1 know-how TAK-580 DOT-1 DOT-1 DOT-1 know-how non-exclusive know-how DOT-1 In consideration for the sale and assignment of assets and the grant of the license under the Takeda Asset Agreement, DOT-1 DOT-1. DOT-1 DOT-1, shares of the Company’s common stock pursuant to and contingent upon the effectiveness of the Conversion (refer to Note 1). The Company recorded a total of million consideration for license and clinical supplies as research and development expenses. The term of the Takeda Asset Agreement will expire on a country-by-country basis upon expiration of all assigned patent rights and all licensed patent rights in such country. Takeda may terminate the Takeda Asset Agreement prior to our first commercial sale of a product if we cease conducting any development activities for a continuous and specified period of time and such cessation is not agreed upon by the parties and is not done in response to guidance from a regulatory authority. Additionally, Takeda can terminate the Takeda Asset Agreement for our bankruptcy. In the event of termination of the Takeda Asset Agreement by Takeda as a result of our cessation of development or bankruptcy, all assigned patents, know-how and contracts (other than the Viracta License Agreement) will be assigned back to Takeda and Takeda will obtain a reversion license under patents and know-how generated to exploit all such terminated products. Viracta License Agreement On December 16, 2019, DOT-1 DOT-1 know-how DOT-1 DOT-1 DOT-1 million upon achievement of specified development and regulatory milestones for each licensed product in two indications, with milestones payable for the second indication to achieve a specified milestone event being lower than milestones payable for the first indication. Additionally, if DOT-1 DOT-1 mid-teen DOT-1 mid-single-digit country-by-country product-by-licensed The term of the Viracta License Agreement will expire on a licensed product-by-licensed country-by-country DOT-1

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. COMMITMENTS AND CONTINGENCIES Leases The Company entered into a lease agreement for its corporate office facility in South San Francisco, California in March 2020, which expires in three years. The Company can extend the lease term for additional three years at market rates upon the notice of extension. The Company is obligated to pay monthly rent expense and its pro rata share of utilities, common area maintenance expenses and property taxes. The landlord also provided an allowance of $10,000 for any tenant improvements. The Company concluded that it is an operating lease. Common area expenses are a non-lease The Company determined the lease incremental borrowing rate (“IBR”) based on the information available at the applicable lease commencement date as the Company’s lease did provide an implicit rate. The IBR is determined by using the rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment where the asset is located. The Company determined the amounts of its lease liabilities using an IBR of 8%. As of June 30, 2021, the remaining lease term was 1.67 years. The Company’s lease does not require any contingent rental payments, impose financial restrictions, or contain any residual value guarantees. Amortization of right-of-use immaterial. As of June 30, 2021, the future lease obligations were as follows (in thousands): Remaining six months in 2021 $ 103 2022 212 2023 18 Total future minimum lease payments 333 Less: Imputed interest (19 ) Present value of operating lease liabilities $ 314 Research and Development Agreements The Company enters into contracts in the normal course of business with clinical research organizations for clinical trials, with contract manufacturing organizations for clinical supplies manufacturing and with other vendors for preclinical studies, supplies and other services and products for operating purposes. These contracts generally provide for termination on notice, with the exception of one vendor with a potential termination fee if a purchase order is cancelled within a specified time and of another vendor where labor costs are non-cancellable . License Agreements The Company entered into the license agreements, as disclosed in Note 7, pursuant to which the Company is required to pay milestones contingent upon meeting of specific events. The first milestone related to the Viracta License Agreement was achieved and recorded to research and development expense during the three months ended June 30, 2021. The Company may be required to pay royalties on sales of products developed under these agreements. All products are in development as of June 30, 2021 and December 31, 2020 and such royalties were due. Legal Proceedings The Company, from time to time, may be party to litigation arising in the ordinary course of business. The Company is not subject to any material legal proceedings, and to the best of its knowledge, no material legal proceedings are currently pending or threatened. Indemnification Agreements In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for indemnification for certain liabilities. The exposure under these agreements is unknown because it involves claims that may be made against it in the future but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations. The Company also has indemnification obligations to its directors and executive officers for specified events or occurrences, subject to some limits, while they are serving at its request in such capacities. There have been no claims to date and the Company believes the fair value of these indemnification agreements is minimal. Accordingly, the Company had not recorded any liabilities for these agreements as of June 30, 2021 and December 31, 2020.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Shares	6 Months Ended
	Jun. 30, 2021
Temporary Equity Disclosure [Abstract]
Redeemable Convertible Preferred Shares	9. REDEEMABLE CONVERTIBLE PREFERRED SHARES In June 2021, the Company completed its IPO, selling an aggregate of 11,500,000 shares of common stock. All outstanding redeemable convertible preferred shares were converted into 32,489,398 shares of common stock upon the completion of the IPO, June 1, 2021. As of June 30, 2021, the Company did not have any outstanding shares of redeemable convertible preferred shares. In February 2021, the Company issued 9,638,141 Series B redeemable convertible preferred shares at a price of $13.488 per share for gross cash proceeds of $130.0 million. The Company incurred issuance costs of $243,000. In December 2019, the Company issued 10,348,507 Series A redeemable convertible preferred shares at a price of $2.899 per share for gross cash proceeds of $30.0 million and issued 2,154,245 shares upon the conversion of the outstanding convertible note and accrued interest of $2.1 million. The Company incurred issuance costs of $95,000. In connection with the initial issuance of the Series A redeemable convertible preferred shares, the Company had an obligation to sell an additional 10,348,505 Series A shares at $2.899 per share upon achievement of certain milestones in two tranche. The Company determined that the obligation to sell additional shares is a freestanding financing instrument and a liability. The Company estimated the fair value of the liability to be $1.5 million and recorded it as a reduction to redeemable convertible preferred shares and as a derivative tranche liability in its condensed consolidated balance sheet at the issuance date in December 2019. For the three months ended March 31, 2020, the Company remeasured the derivative tranche liability by $0.2 million. In November and December 2020, the Board approved the settlement of tranche and the Company issued 10,348,505 shares for gross cash proceeds of $30.0 million. The Company incurred issuance costs of $22,000. As of December 31, 2020, no derivative tranche liabilities were outstanding. The authorized, issued, and outstanding Series A redeemable convertible preferred shares as of December 31, 2020 were as follows: December 31, 2020 Shares Shares Liquidation Carrying Series A redeemable convertible preferred shares 22,851,257 22,851,257 $ 66,245,059 $ 91,964,055

Common Shares_Common Stock

Common Shares/Common Stock	6 Months Ended
	Jun. 30, 2021
Stockholders' Equity Note [Abstract]
Common Shares/Common Stock	10. COMMON SHARES/COMMON STOCK Upon completion of the IPO, the Company is authorized to issue .0 million shares of common stock at a par value $ . As of June 30, 2021, shares of common stock were issued and outstanding. As of December 31, 2020, the Company was authorized to issue 28,887,127 common shares. Common shares’ holders are entitled to vote and elect one Board member. As of December 31, 2020, the Company had 6,035,869 issued and outstanding common shares. As of December 31, 2020, the Company reserved 22,851,257 shares upon conversion of redeemable convertible preferred shares into common shares, respectively. In November 2018, the Company entered into common shares purchase agreements with two founders of the Company. The individuals purchased a total of 2,790,000 common shares for a total purchase price of $300. Shares vest monthly for two of the original price per share paid by the founder for such stock or the fair value as of the date of such repurchase. As of December 31, 2020, there were 193,766 shares unvested. The founders’ shares were converted to common stock in the Conversion. As of June 30, 2021, all founders’ common stock were vested .

Incentive Shares and Share_Stoc

Incentive Shares and Share/Stock-Based Compensation	6 Months Ended
	Jun. 30, 2021
Stockholders' Equity Note [Abstract]
Incentive Shares and Share/Stock-Based Compensation	11. INCENTIVE SHARES AND SHARE/STOCK-BASED COMPENSATION Prior to the Conversion, Day One Holding LLC granted incentive shares under the Incentive Share Plan and was authorized to issue 8,924,177 incentive shares. Incentive shares were a separate non-voting Day One non-employees, award-by-award The fair value of the incentive shares was estimated using an option pricing model with the following assumptions: Three Months Ended Six Months Ended 2021 (through 2020 2021 2020 Common share fair value $ 8.89 $ 0.89 $ 6.36 $ 0.81 Participating threshold $ 7.51 $ 0.27 $ 6.36 $ 0.27 Risk free rate 0.14 % 0.18 % 0.14 % 0.18% - 0.3 % Volatility 72.90% 80.00 % 72.90 % 78 % Time to liquidity (in years) 0.20 3.03 0.20 3.03 Grant date fair value $ 4.24 $ 0.74 $ 4.24 $ 0.71 The Company used the option pricing model to estimate the fair value of each incentive shares award on the date of grant. The members’ equity value was based on a recent enterprise valuation analysis performed and common share fair value. The participation threshold amounts are determined by the Board at the time of grant. The expected life of the awards granted during the period was determined based on an expected time to the liquidation event. The Company applied the risk-free interest rate based on the U.S. Treasury yield in effect at the time of the grant consistent with the life of the award. The expected volatility is based on a peer group in the industry in which the Company does business consistent with the expected time to liquidity. The dividend yield was set at zero as the underlying security does not and is not expected to pay a dividend. Fair Value of Common Share Prior to the IPO, management’s approach to estimate the fair value of the common share is consistent with the methods outlined in the American Institute of Certified Public Accountants’ Practice Aid, Valuation of Privately-Held-Company Equity Securities Issued as Compensation ( Company’s redeemable convertible preferred shares relative to those of common shares; the likelihood of achieving a liquidity event for the holders of the common and redeemable convertible preferred shares, such as an initial public offering or a sale, given prevailing market conditions. The fair value of the common shares was approved by the Board until such time as the Company shares are listed on an established stock exchange or national market system. The incentive shares have been classified as equity awards and share-based compensation expense was based on the grant date fair value of the award. The following table provides a summary of the incentive shares activity: Number of Weighted Outstanding as of December 31, 2020 4,112,017 $ 1.26 Granted 2,959,795 $ 4.32 Forfeited (265,596 ) $ 1.67 Converted to unvested common stock (6,806,216 ) $ 2.58 Outstanding as of June 30, 2021 — 2021 Stock Incentive Plan Immediately prior to consummation of the IPO, all of the outstanding incentive shares were converted into 5,433,290 shares of common stock, of which 4,719,605 were unvested common stock. The following table provides a summary of the unvested common stock grant activity during the six months ended June 30, 2021. Number of Weighted Unvested restricted stock as of December 31, 2020 — $ — Conversion of incentive shares 4,719,605 $ 16.00 Vested (36,489 ) $ 16.00 Unvested restricted stock as of June 30, 2021 4,683,116 $ 16.00 In May 2021, in connection with the IPO, the Board of Directors and stockholders approved the 2021 Equity Incentive Plan (the “2021 Plan”), which became effective on the day before the date of the effectiveness of the IPO. The 2021 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, awards of restricted stock, restricted stock units and other stock-based awards. The number of shares of common stock reserved for issuance under the 2021 Plan is equal to the sum of: (1) 6,369,000; plus (2) 4,719,605 shares of common stock issued in respect of the Conversion of incentive shares that were subject to vesting immediately prior to the effectiveness of the registration statement for the IPO that expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by us at their original issuance price pursuant to a contractual repurchase right. The number of shares available for grant and issuance under the 2021 Plan will be automatically increased on January 1 of each of 2022 through 2031, by the lesser of (a) 5% of the number of shares of all classes of the Company’s common stock, plus the total number of shares of Company common stock issuable upon conversion of any preferred stock or exercise of any warrants to acquire shares of Company common stock for a nominal exercise price issued and outstanding on each December 31 immediately prior to the date of increase or (b) such number of shares determined by the Board of Directors. The Company issued 4,418,874 stock options with at weighted average fair value of $9.30 upon effectiveness of the IPO during the three months ended June 30, 2021. The intrinsic value of outstanding options is $29.9 million and remaining contractual life of 9.9 years as of June 30, 2021. The following table provides a summary of stock option activity under the 2021 Plan during the six months ended June 30, 2021. Number of Weighted Outstanding at December 31, 2020 — $ — Granted 4,418,874 $ 16.00 Outstanding at June 30, 2021 4,418,874 $ 16.00 Exercisable at June 30, 2021 21,622 $ 16.00 2021 Employee Stock Purchase Plan In May 2021, the Board of Directors adopted and the stockholders approved the 2021 Employee Stock Purchase Plan, (“the ESPP”), which became effective on May 26, 2021. A total of 603,000 shares of common stock were reserved for issuance under the ESPP. The number of shares of the common stock reserved for issuance under the ESPP will automatically increase on the first day of each fiscal year, beginning with the fiscal year commencing on January 1, 2021 and continuing for each fiscal year until, and including, the fiscal year commencing on January 1, 2031, by the lesser of: a) 1% of the total number of outstanding shares of common stock of the Company (on an as converted basis outstanding on the immediately preceding December 31 (rounded down to the nearest whole share); b) an amount determined by the Board of Directors. No shares have been issued under the ESPP as of June 30, 2021 . Share/Stock-based compensation The Company recorded share/stock-based compensation expense related to the issuance of incentive shares and stock options of $3.1 million and $0.1 million during the six months ended June 30, 2021 and 2020, respectively, and $2.5 million and $0.1 million during the three months ended June 30, 2021 and 2020, respectively. As of June 30, 2021, there was $39.6 million of unrecognized compensation cost related to unvested restricted stock and stock options that is expected to be recognized over a weighted-average period of approximately 3.0 years. As of June 30, 2020, there was $0.7 million of unrecognized compensation cost related to unvested incentive shares that is expected to be recognized over a weighted-average period of approximately 2.9 years. The Company uses intrinsic value to value its unvested common stock and stock options, which is the difference between the Company’s common stock market value and the exercise price of a share and recognizes expense over the vesting term of the award. The Company uses the Black-Scholes option pricing model to estimate the fair value of stock option granted with the following assumption for awards granted in May 2021: Common stock fair value $ 16.00 Expected term (in years) 5.28 Expected volatility 64.91% % Risk-free interest rate 0.86% - 1.00% Expected dividend yield — Share/stock-based compensation expense recorded in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Loss is as follows (in thousands): Three Months Ended Six Months Ended 2021 2020 2021 2020 Research and development expense $ 713 $ 55 $ 832 $ 69 General and administrative expense 1,824 2 2,243 47 Total share-based compensation expense $ 2,537 $ 57 $ 3,075 $ 116

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Net Loss Per Share	12. NET LOSS PER SHARE Net Loss Per Share Basic and diluted net loss per share attributable to common shareholders/stockholders after the Conversion is calculated as follows (in thousands except share and per share amounts): Three Months Ended Six Months Ended 2021 2020 2021 2020 Net loss and comprehensive loss $ (15,473 ) $ (2,409 ) $ (31,575 ) $ (4,401 ) Net loss attributable to redeemable convertible noncontrolling interests (1,191 ) (649 ) (2,109 ) (1,106 ) Exchange of redeemable noncontrolling interest (r efer to Not e 13) (99,994 ) — (99,994 ) — Net loss attributable to common share members/common stockholders (114,276 ) (1,760 ) (129,460 ) (3,295 ) Net loss per share, basic and diluted $ (5.04 ) $ (0.32 ) $ (10.81 ) $ (0.61 ) Weighted-average number of common shares used in computing net loss per share, basic and diluted 22,661,889 5,456,203 11,976,577 5,383,549 The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive: As of 2021 2020 Redeemable convertible preferred shares — 12,502,752 Incentive shares — 683,379 Stock options 4,418,874 — Unvested common shares 4,683,116 484,391 9,101,990 13,670,522

Redeemable NonControlling Inter

Redeemable NonControlling Interest	6 Months Ended
	Jun. 30, 2021
Temporary Equity Disclosure [Abstract]
Redeemable NonControlling Interest	13. REDEEMABLE NONCONTROLLING INTEREST DOT-1, The Company adjusts the carrying value of redeemable noncontrolling interest to allocate net losses of the subsidiary to Takeda. Transfers to and from the redeemable noncontrolling interest represent changes in ownership and the allocation of Series A redeemable convertible preferred shares issuance costs issued by the subsidiary . On May 26, 2021, pursuant to the pursuant to the terms of the Millennium Stock Exchange Agreement, Takeda exchanged its 9,857,143 shares of Series A redeemable convertible preferred stock in DOT -1, Exchange May 26, 2021 and from April 1 to May 26, 2021, respectively, to Takeda. The E -1 all-stock

Summary of Significant Accou_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), and follow the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain notes and other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of the Company’s financial information. The condensed consolidated balance sheet as of December 31, 2020 has been derived from audited consolidated financial statements as of that date but does not include all of the financial information required by U.S. GAAP for complete financial statements. Operating results for the six months ended June 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”) .
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to, the fair value of the redeemable convertible preferred shares, the fair value of the common shares, the fair value of the derivative tranche liability, the valuation of share-based awards, the valuation of deferred tax assets and income tax uncertainties, and accruals for research and development activities. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable. Actual results may differ from those estimates or assumptions.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. As of June 30, 2021, cash equivalents include investments in money market funds. As of December 31, 2020, the Company did not have any cash equivalents and cash was held in checking accounts.
Deferred Finance Issuance Costs	Deferred Finance Issuance Costs Deferred finance issuance costs, consisting of legal, accounting, audit and filing fees relating to in-process
Share/Stock-Based Compensation	Share/Stock-Based Compensation Prior to the IPO, the Company recognized share-based compensation expense based on the estimated fair value of all share-based awards, incentive shares and restricted common share shares, on the date of grant using the option-pricing model. The option-pricing model requires the input of subjective assumptions, including the fair value of the underlying common shares, the expected term of the award, the expected volatility, risk-free interest rates, and the dividend yield. In determining the fair value of common shares, the methodologies used to estimate the enterprise value were performed using methodologies, approaches, and assumptions consistent with the American Institute of Certified Public Accountants Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation dividend. Subsequent to closing of the IPO, the Company uses the Black-Scholes valuation model to estimate the fair value of options granted to employees and non-employees, The Black-Scholes option-pricing model, used to estimate fair value of stock options awards, requires the use of the following assumptions: • Fair Value of Common Stock • Expected Term • Expected Volatility • Risk-Free Interest Rate grant for zero-coupon U.S. Treasury • Expected Dividend Yield The Company uses the straight-line attribution method for recognizing share/stock-based compensation expense. The Company recognizes forfeitures by reducing the expense in the same period the forfeitures occur. The Company recognizes share/stock-based compensation expense for awards with performance conditions when it is probable that the condition will be met, and the award will vest. The Company classifies share/stock-based compensation expense in the Consolidated Statement of Operations and Comprehensive Loss in the same manner in which the award recipients’ payroll costs are classified or in which the award recipients’ service payments are classified.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326). 2016-13 2016-13 2019-04, 2016-13 In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes 2019-12”), 2019-12 2019-12 In August 2020, the FASB issued ASU No. 2020-06 (“ASU 2020-06”) Debt—Debt with Conversion and Other Options (Subtopic 470-20) 815-40): 2020-06 will paid-in 2020-06 also

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table sets forth the Company’s financial instruments as of June 30, 2021 and December 31, 2020, which are measured at fair value on a recurring basis by level within the fair value hierarchy. These are classified based on the lowest level of input that is significant to the fair value measurement (in thousands): June 30, 2021 Total Level 1 Level 2 Level 3 Money market funds, included in cash and cash equivalents $ 136,876 $ 136,876 $ — $ —

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	6 Months Ended
	Jun. 30, 2021
Prepaid Expense and Other Assets, Current [Abstract]
Schedule of Prepaid and Other Current Assets	Prepaid and other current assets consisted of the following (in thousands): June 30, December 31, Prepaid insurance $ 4,578 $ 41 Prepaid research and development expenses 1,277 1,259 Other prepaid expenses and other assets 174 43 Total prepaid expenses and other current assets $ 6,029 $ 1,343

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	6 Months Ended
	Jun. 30, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment, net, consisted of the following (in thousands): June 30, December 31, Furniture and fixtures $ 78 $ 78 Leasehold improvements 15 15 Less: accumulated depreciation and amortization (26 ) (16 ) Property and equipment, net $ 67 $ 77

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
Payables and Accruals [Abstract]
Schedule of Accrued expenses and other current liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): June 30, December 31, Accrued research and development expenses $ 1,642 $ 554 Accrued professional service expenses 913 298 Accrued payroll related expenses 849 717 Accrued issuance costs 615 — Other 94 27 Total accrued expenses and other current liabilities $ 4,113 $ 1,596

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Summary of Future Lease Obligations	As of June 30, 2021, the future lease obligations were as follows (in thousands): Remaining six months in 2021 $ 103 2022 212 2023 18 Total future minimum lease payments 333 Less: Imputed interest (19 ) Present value of operating lease liabilities $ 314

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Shares (Tables)	6 Months Ended
	Jun. 30, 2021
Temporary Equity Disclosure [Abstract]
Summary of Series A Redeemable Convertible Preferred Shares	The authorized, issued, and outstanding Series A redeemable convertible preferred shares as of December 31, 2020 were as follows: December 31, 2020 Shares Shares Liquidation Carrying Series A redeemable convertible preferred shares 22,851,257 22,851,257 $ 66,245,059 $ 91,964,055

Incentive Shares and Share_St_2

Incentive Shares and Share/Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Summary of Fair Value of The Incentive Shares Estimated Using An Option Pricing Model	The fair value of the incentive shares was estimated using an option pricing model with the following assumptions: Three Months Ended Six Months Ended 2021 (through 2020 2021 2020 Common share fair value $ 8.89 $ 0.89 $ 6.36 $ 0.81 Participating threshold $ 7.51 $ 0.27 $ 6.36 $ 0.27 Risk free rate 0.14 % 0.18 % 0.14 % 0.18% - 0.3 % Volatility 72.90% 80.00 % 72.90 % 78 % Time to liquidity (in years) 0.20 3.03 0.20 3.03 Grant date fair value $ 4.24 $ 0.74 $ 4.24 $ 0.71
Summary of The Incentive Shares Activity	The following table provides a summary of the incentive shares activity: Number of Weighted Outstanding as of December 31, 2020 4,112,017 $ 1.26 Granted 2,959,795 $ 4.32 Forfeited (265,596 ) $ 1.67 Converted to unvested common stock (6,806,216 ) $ 2.58 Outstanding as of June 30, 2021 —
Summary of The Unvested Common Stock	Immediately prior to consummation of the IPO, all of the outstanding incentive shares were converted into 5,433,290 shares of common stock, of which 4,719,605 were unvested common stock. The following table provides a summary of the unvested common stock grant activity during the six months ended June 30, 2021. Number of Weighted Unvested restricted stock as of December 31, 2020 — $ — Conversion of incentive shares 4,719,605 $ 16.00 Vested (36,489 ) $ 16.00 Unvested restricted stock as of June 30, 2021 4,683,116 $ 16.00
Summary of Stock Option Activity Under The 2021 Plan	The following table provides a summary of stock option activity under the 2021 Plan during the six months ended June 30, 2021. Number of Weighted Outstanding at December 31, 2020 — $ — Granted 4,418,874 $ 16.00 Outstanding at June 30, 2021 4,418,874 $ 16.00 Exercisable at June 30, 2021 21,622 $ 16.00
Summary of The Black-Scholes Option Pricing Model to Estimate The Fair Value of Stock Option Granted	Common stock fair value $ 16.00 Expected term (in years) 5.28 Expected volatility 64.91% % Risk-free interest rate 0.86% - 1.00% Expected dividend yield —
Summary of Share/Stock-based Compensation Expense Recorded in The Accompanying Condensed Consolidated Statements of Operations and Comprehensive Loss	Share/stock-based compensation expense recorded in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Loss is as follows (in thousands): Three Months Ended Six Months Ended 2021 2020 2021 2020 Research and development expense $ 713 $ 55 $ 832 $ 69 General and administrative expense 1,824 2 2,243 47 Total share-based compensation expense $ 2,537 $ 57 $ 3,075 $ 116

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Summary of Basic and Diluted Net Loss Per Share Attributable to Common Shareholders/Stockholders	Basic and diluted net loss per share attributable to common shareholders/stockholders after the Conversion is calculated as follows (in thousands except share and per share amounts): Three Months Ended Six Months Ended 2021 2020 2021 2020 Net loss and comprehensive loss $ (15,473 ) $ (2,409 ) $ (31,575 ) $ (4,401 ) Net loss attributable to redeemable convertible noncontrolling interests (1,191 ) (649 ) (2,109 ) (1,106 ) Exchange of redeemable noncontrolling interest (r efer to Not e 13) (99,994 ) — (99,994 ) — Net loss attributable to common share members/common stockholders (114,276 ) (1,760 ) (129,460 ) (3,295 ) Net loss per share, basic and diluted $ (5.04 ) $ (0.32 ) $ (10.81 ) $ (0.61 ) Weighted-average number of common shares used in computing net loss per share, basic and diluted 22,661,889 5,456,203 11,976,577 5,383,549
Summary of Outstanding Potentially Dilutive Securities Have Been Excluded From Calculation of Diluted Net Loss Per Share	The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive: As of 2021 2020 Redeemable convertible preferred shares — 12,502,752 Incentive shares — 683,379 Stock options 4,418,874 — Unvested common shares 4,683,116 484,391 9,101,990 13,670,522

Description Of Business, Orga_2

Description Of Business, Organization And Liquidity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jun. 01, 2021	May 23, 2021	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from issuance of initial public offering	$ 167,000
Payments of stock issuance costs	$ 17,000
Share-based compensation arrangement by share-based payment award, options, vested, number of shares			4,719,605
Common stock shares authorized			500,000,000
Preferred stock shares authorized			10,000,000	0
Preferred stock par or stated value per share			$ 0.0001	$ 0.0001
Stockholders' equity note, stock split		2.325-for-1
Retained Earnings (Accumulated Deficit)			$ (86,308)	$ (56,842)
Cash and cash equivalents			$ 309,996	$ 43,728	$ 23,266	$ 27,332
IPO [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Stock issued during period, shares, new issues	11,500,000		11,500,000
Shares issued, price per share	$ 16		$ 16
Number of shares issued upon conversion			5,433,290
Stock issued during period, shares, conversion of units			32,489,398
Share-based compensation arrangement by share-based payment award, options, grants in period, net of forfeitures			4,418,874
Over-Allotment Option [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Stock issued during period, shares, issued for services	1,500,000
Series A Redeemable Convertible Preferred Stock [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock par or stated value per share			$ 0.0001
Series A Redeemable Convertible Preferred Stock [Member] | Millennium Pharmaceuticals, Inc. [Member] | The Millennium Stock Exchange Agreement [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Conversion of stock, shares converted			9,857,143
Convertible preferred stock, shares issued upon conversion			6,470,382

Summary of Significant Accou_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Accounting Policies [Line Items]
Cash equivalents, at carrying value		$ 0
Cash		0
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected dividend payments	$ 0
Series B redeemable convertible preferred shares [Member]
Accounting Policies [Line Items]
Deferred finance costs, own-share lending arrangement, issuance costs, net	$ 0	$ 36,000

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Company's Financial Instruments (Detail) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents		$ 0
Fair Value, Recurring [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	$ 136,876,000
Fair Value, Recurring [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	136,876,000
Fair Value, Recurring [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents
Fair Value, Recurring [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value disclosure		$ 0
Fair value, measurement recurring basis, asset, transfers, net	$ 0

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Summary of Prepaid and Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid insurance	$ 4,578	$ 41
Prepaid research and development expenses	1,277	1,259
Other prepaid expenses and other assets	174	43
Total prepaid expenses and other current assets	$ 6,029	$ 1,343

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Less: accumulated depreciation and amortization	$ 26	$ 16
Property and equipment, net	67	77
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	78	78
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 15	$ 15

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued expenses and other current liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued research and development expenses	$ 1,642	$ 554
Accrued professional service expenses	913	298
Accrued payroll related expenses	849	717
Accrued issuance costs	615
Other	94	27
Total accrued expenses and other current liabilities	$ 4,113	$ 1,596

Significant Agreements - Additi

Significant Agreements - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 16, 2019	Feb. 28, 2021	Jun. 30, 2021	Jun. 30, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock Issued During Period, Value, New Issues			$ 167,045
Common Stock [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock Issued During Period, Shares, New Issues			11,500,000
Stock Issued During Period, Value, New Issues			$ 1
Merck License Agreement [Member] | Research and Development Expense [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of Milestones				$ 367,000
Takeda Asset Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront of cash payment	$ 1,000
Takeda Asset Agreement [Member] | Common Stock [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock Issued During Period, Value, Conversion of Convertible Securities	$ 6,470,382
Takeda Asset Agreement [Member] | Series A Redeemable Convertible Preferred Stock [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock Issued During Period, Shares, New Issues	9,857,143
Stock Issued During Period, Value, New Issues	$ 9,900
Stock Issued During Period, Shares, Conversion of Convertible Securities	9,857,143
Takeda Asset Agreement [Member] | Research and Development Expense [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment				$ 8,000
Aggregate cash consideration paid	$ 10,900
Viracta License Agreement [Member] | Maximum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of Milestones		$ 54,000
Viracta License Agreement [Member] | Research and Development Expense [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of Milestones		$ 3,000
Upfront of cash payment	$ 2,000

Commitment and Contingencies -

Commitment and Contingencies - Summary of Future Lease Obligations (Detail) $ in Thousands	Jun. 30, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining six months in 2021	$ 103
2022	212
2023	18
Total future minimum lease payments	333
Less: Imputed interest	(19)
Present value of operating lease liabilities	$ 314

Commitment and Contingencies _2

Commitment and Contingencies - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Amortization of right of use asset operating lease	$ 88,000	$ 55,000
Research And Development Agreements [Member]
Lessee, Lease, Description [Line Items]
Termination and cancellation charges payable	0		$ 0
Litigation amount awarded from other party	0		0
Viracta License Agreement [Member]
Lessee, Lease, Description [Line Items]
Royalty fee payable	0		0
Indemnification Agreement [Member]
Lessee, Lease, Description [Line Items]
Termination and cancellation charges payable	0		0
Litigation amount awarded from other party	$ 0		$ 0
Lease For Corporate Office Facility [Member] | Central America [Member]
Lessee, Lease, Description [Line Items]
Operating lease term	3 years
Tenant improvement allowances receivable	$ 10,000
Lessee operating lease incremental borrowing rate		8.00%
Lessee operating lease renewal lease term	3 years	1 year 8 months 1 day
Amortization of right of use asset operating lease	$ 88,000	$ 55,000
Operating lease payments	$ 102,000	$ 73,000

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Shares - Additional Information (Detail) - USD ($)	Jun. 01, 2021	Feb. 28, 2021	Dec. 31, 2020	Nov. 30, 2020	Dec. 31, 2019	Jun. 30, 2020	Jun. 30, 2021
Temporary Equity [Line Items]
Payment of stock issuance costs	$ 17,000,000
IPO [Member]
Temporary Equity [Line Items]
Issuance of incentive shares	11,500,000						11,500,000
Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Common stock shares issued as a result of conversion of temporary equity into permanent equity							32,489,398
Temporary equity, shares outstanding							0
Series A Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary equity stock issued during the period shares new issues					10,348,507
Temporary equity issue price per share					$ 2.899
Proceeds from redeemable convertible preferred stock					$ 30,000,000
Payment of accrued interest					2,100,000
Payment of stock issuance costs					$ 95,000
Temporary equity shares issued upon conversion of notes payable					2,154,245
Series A Redeemable Convertible Preferred Stock [Member] | Milestone Achieved [Member]
Temporary Equity [Line Items]
Temporary equity stock issued during the period shares new issues				10,348,505
Proceeds from redeemable convertible preferred stock				$ 30,000,000
Payment of stock issuance costs				$ 22,000
Series A Redeemable Convertible Preferred Stock [Member] | Temporary Equity Related Tranche Liability [Member]
Temporary Equity [Line Items]
Unrealized gain loss due to change in fair value of derivatives						$ 200,000
Derivative liability at fair value						$ 1,500,000
Series A Redeemable Convertible Preferred Stock [Member] | Milestone Achievement [Member]
Temporary Equity [Line Items]
Temporary equity stock issued during the period shares new issues			10,348,505
Temporary equity issue price per share						$ 2.899
Proceeds from redeemable convertible preferred stock			$ 30,000,000
Payment of stock issuance costs			22,000
Temporary equity shares subscribed but not issued						10,348,505
Derivative liability at fair value			$ 0
Series B Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary equity stock issued during the period shares new issues		9,638,141
Temporary equity issue price per share		$ 13.488
Payment of stock issuance costs		$ 243,000
Series B Redeemable Convertible Preferred Stock [Member] | Gross Proceeds [Member]
Temporary Equity [Line Items]
Proceeds from redeemable convertible preferred stock		$ 130,000,000

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Shares - Summary of Series A Redeemable Convertible Preferred Shares (Detail)	Dec. 31, 2020USD ($)shares
Temporary Equity [Line Items]
Carrying Value | $	$ 91,964,000
Series A Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Shares Authorized | shares	22,851,257
Shares Issued | shares	22,851,257
Shares Outstanding | shares	22,851,257
Liquidation Value | $	$ 66,245,059
Carrying Value | $	$ 91,964,055

Common Shares_Common Stock - Ad

Common Shares/Common Stock - Additional Information (Detail)	1 Months Ended	6 Months Ended
	Nov. 30, 2018USD ($)shares	Jun. 30, 2021USD ($)$ / sharesshares	Dec. 31, 2020$ / sharesshares
Class of Stock [Line Items]
Common Stock, Shares Authorized		500,000,000
Common Stock, Shares Issued		61,928,939	6,035,869
Common Stock, Shares Outstanding		61,928,939	6,035,869
Number of directors entitled to be elected by the holders of common stock			1
Proceeds from the issuance of common stock | $		$ 167,660,000
Common Shares Purchase Agreement [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized		500,000,000	28,887,127
Founder [Member]
Class of Stock [Line Items]
Common stock shares unvested			193,766
Founder [Member] | Common Shares Purchase Agreement [Member]
Class of Stock [Line Items]
Issuance of incentive shares	2,790,000
Proceeds from the issuance of common stock | $	$ 300
Founder One [Member] | Common Shares Purchase Agreement [Member]
Class of Stock [Line Items]
Common stock shares issued vesting term	2 years
Founder Two [Member] | Common Shares Purchase Agreement [Member]
Class of Stock [Line Items]
Common stock shares issued vesting term	4 years
Redeemable Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Common stock shares reserved for future issuance			22,851,257
Common Class B [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized		500,000,000	0
Common Stock, Par or Stated Value Per Share | $ / shares		$ 0.0001	$ 0.0001
Common Stock, Shares Issued		61,928,939	0
Common Stock, Shares Outstanding		61,928,939	0

Incentive Shares and Share_St_3

Incentive Shares and Share/Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	May 31, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share based compensation expense		$ 2,537	$ 57	$ 3,075	$ 116
Incentive Share Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment award fair value assumptions dividend yield				0.00%
Incentive Share Plan [Member] | Day One Holding LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangment number of shares authorized		8,924,177		8,924,177
Incentive Share Plan [Member] | Cliff Vesting [Member] | Day One Holding LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement term of vesting				12 months
2021 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion of shares of one class into another				5,433,290
2021 Stock Incentive Plan [Member] | Unvested Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion of shares of one class into another				4,719,605
2021 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance	6,369,000
Additional number of common stock shares reserved for future issuance	4,719,605
Share based compensation by share based payment arrangement non vested options granted during the period				4,418,874
Share based compensation by share based payment arrangement non vested options granted during the period weighted average grant date fair value				$ 16
Share based compensation by share based arrangement intrinsic value of non vested outstanding options		$ 29,900		$ 29,900
Share based compensation by share based payment arrangement weighted average remaining contractual life of non vested outstanding options		9 years 10 months 24 days
2021 Equity Incentive Plan [Member] | IPO [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement non vested options granted during the period		4,418,874
Share based compensation by share based payment arrangement non vested options granted during the period weighted average grant date fair value		$ 9.30
2021 Equity Incentive Plan [Member] | Incremental Shares Reserved for Future Issuance [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional number of common stock shares reserved for future issuance as percentage of common stock shares outstanding	5.00%
2021 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance	603,000
Additional number of common stock shares reserved for future issuance as percentage of common stock shares outstanding	1.00%
2021 Employee Stock Purchase Plan [Member] | Incentive Shares and Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share based compensation expense		$ 2,500	100	3,100	100
2021 Employee Stock Purchase Plan [Member] | Unvested Restricted Stock and Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement unrecognized compensation		$ 39,600		$ 39,600
Share based compensation by share based payment arrangement unrecognized compensation remaining period for recognition				3 years
2021 Employee Stock Purchase Plan [Member] | Unvested Incentive Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement unrecognized compensation			$ 700		$ 700
Share based compensation by share based payment arrangement unrecognized compensation remaining period for recognition					2 years 10 months 24 days

Incentive Shares and Share_St_4

Incentive Shares and Share/Stock-Based Compensation - Summary of Fair Value of The Incentive Shares Estimated Using An Option Pricing Model (Detail) - Incentive Share Plan Member [Member] - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common share fair value	$ 8.89	$ 0.89	$ 8.89	$ 0.89
Participating threshold	$ 7.51	$ 0.27	$ 7.51	$ 0.27
Risk free rate	0.14%	0.18%	0.14%
Risk free rate, minimum				0.18%
Risk free rate, maximum				0.30%
Volatility	72.90%	80.00%	72.90%
Volatility, minimum				78.00%
Volatility, maximum				80.00%
Time to liquidity (in years)		3 years 10 days
Grant date fair value	$ 4.24	$ 0.74
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common share fair value	8.89	0.89	$ 8.89	$ 0.89
Participating threshold	$ 7.51		$ 7.51
Time to liquidity (in years)	2 months 12 days		1 year 9 months 18 days	3 years 3 months 18 days
Grant date fair value			$ 4.52	$ 0.74
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common share fair value	$ 6.36	$ 0.81	6.36	$ 0.81
Participating threshold	$ 6.36		$ 6.36
Time to liquidity (in years)	1 year 9 months 18 days		2 months 12 days	3 years 10 days
Grant date fair value			$ 4.24	$ 0.71

Incentive Shares and Share_St_5

Incentive Shares and Share/Stock-Based Compensation - Summary of The Incentive Shares Activity (Detail) - Incentive Shares [Member]	6 Months Ended
	Jun. 30, 2021$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding at December 31, 2020	4,112,017
Number of Shares, Granted	2,959,795
Number of Shares, Forfeited	(265,596)
Number of Shares, Converted to unvested common stock	(6,806,216)
Number of Shares, Outstanding at June 30, 2021	0
Weighted Average Grant Date Fair Value, Outstanding | $ / shares	$ 1.26
Weighted Average Grant Date Fair Value, Granted | $ / shares	4.32
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	1.67
Weighted Average Grant Date Fair Value, Converted to unvested common stock | $ / shares	$ 2.58

Incentive Shares and Share_St_6

Incentive Shares and Share/Stock-Based Compensation - Summary of The Unvested Common Stock (Detail) - 2021 Stock Incentive Plan [Member] - Restricted Stock [Member]	6 Months Ended
	Jun. 30, 2021$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Beginning balance | shares	0
Conversion of incentive shares | shares	4,719,605
Vested | shares	(36,489)
Number of Shares, Ending balance | shares	4,683,116
Weighted Average Grant Date Fair Value, Beginning balance | $ / shares	$ 0
Conversion of incentive shares | $ / shares	16
Vested | $ / shares	16
Weighted Average Grant Date Fair Value, Ending balance | $ / shares	$ 16

Incentive Shares and Share_St_7

Incentive Shares and Share/Stock-Based Compensation - Summary of Stock Option Activity Under The 2021 Plan (Detail) - Two Thousand And Twenty One Equity Incentive Plan [Member] - $ / shares	6 Months Ended
	Jun. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Beginning balance	0
Granted	4,418,874
Number of Shares, Ending balance	4,418,874
Exercisable	21,622
Weighted average grant date fair value, beginning	$ 0
Granted	16
Weighted average grant date fair value, Ending	16
Weighted average grant date fair value, Exercisable	$ 16

Incentive Shares and Share_St_8

Incentive Shares and Share/Stock-Based Compensation - Summary of The Black-Scholes Option Pricing Model to Estimate The Fair Value of Stock Option Granted (Detail) - Two Thousand And Twenty One Equity Incentive Plan [Member] - Stock options [Member]	6 Months Ended
	Jun. 30, 2021$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Price	$ 16
Volatility, minimum	64.91%
Volatility, maximum	66.51%
Risk free rate, minimum	0.86%
Risk free rate, maximum	1.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 10 months 24 days
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 3 months 10 days

Incentive Shares and Share_St_9

Incentive Shares and Share/Stock-Based Compensation - Summary of Share/Stock-based Compensation Expense Recorded in The Accompanying Condensed Consolidated Statements of Operations and Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	$ 2,537	$ 57	$ 3,075	$ 116
Research and Development Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	713	55	832	69
General and Administrative Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	$ 1,824	$ 2	$ 2,243	$ 47

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share Attributable to Common Shareholders/Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net loss and comprehensive loss	$ (15,473)	$ (2,409)	$ (31,575)	$ (4,401)
Net loss attributable to redeemable convertible noncontrolling interests	(1,191)	(649)	(2,109)	(1,106)
Exchange of redeemable noncontrolling interest shares – deemed dividend (refer to Note 13)	(99,994)	0	(99,994)	0
Net loss attributable to common share members/common stockholders	$ (114,276)	$ (1,760)	$ (129,460)	$ (3,295)
Net loss per share, basic and diluted	$ (5.04)	$ (0.32)	$ (10.81)	$ (0.61)
Weighted-average number of common shares used in computing net loss per share, basic and diluted	22,661,889	5,456,203	11,976,577	5,383,549

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of Outstanding Potentially Dilutive Securities Have Been Excluded From Calculation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	9,101,990	13,670,522
Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		12,502,752
Incentive Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		683,379
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	4,418,874
Unvested common shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	4,683,116	484,391

Redeemable NonControlling Int_2

Redeemable NonControlling Interest - Additional Information (Detail) - USD ($) $ in Thousands	May 26, 2021	May 26, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Redeemable Noncontrolling Interest [Line Items]
Net loss attributable to redeemable convertible noncontrolling interests			$ 1,191	$ 649	$ 2,109	$ 1,106
Adjustment to additional paid in capital loss on conversion of temporary equity into permanent equity		$ 100,000
DOT -1 [Member]
Redeemable Noncontrolling Interest [Line Items]
Temporary equity shares converted into permanent equity	9,857,143
Common stock shares issued as a result of conversion of temporary equity into permanent equity	6,470,382
DOT -1 [Member] | Takeda [Member]
Redeemable Noncontrolling Interest [Line Items]
Net loss attributable to redeemable convertible noncontrolling interests	$ 2,100	$ 900