0000950170-22-022667 | 10-Q | XBRL Viewer | DAY ONE Biopharmaceuticals INC

Print Document View Excel Document

Share-based Compensation - Summary of Fair Value of The Incentive Shares Estimated Using An Option Pricing Model (Detail) - Incentive Share Plan Member [Member]	9 Months Ended
	Sep. 30, 2021 $ / shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	0.14%
Volatility	72.90%
Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common share fair value	$ 8.89
Participating threshold	$ 7.51
Time to liquidity (in years)	1 year 9 months 18 days
Grant date fair value	$ 4.52
Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common share fair value	6.36
Participating threshold	$ 6.36
Time to liquidity (in years)	2 months 12 days
Grant date fair value	$ 4.24

Share-based Compensation - Summary of Stock Option Activity Under The 2021 Plan (Detail) - Two Thousand And Twenty One Equity Incentive Plan [Member] $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($) $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Beginning Balance \| shares	5,071,896
Granted \| shares	2,868,380
Exercised \| shares	130,899
Forfeiture \| shares	(361,569)
Number of Shares, Ending Balance \| shares	7,447,808
Exercisable at June 30, 2022 \| shares	1,927,895
Weighted Average Exercise Price Per Share, Beginning Balance \| $ / shares	$ 16.90
Granted \| $ / shares	14.81
Exercised \| $ / shares	15.95
Forfeiture \| $ / shares	15.09
Weighted Average Exercise Price Per Share, Ending Balance \| $ / shares	16.20
Exercisable at June 30, 2022 \| $ / shares	$ 16.35
Weighted-Average Remaining Contractual Term, Outstanding at June 30, 2022	8 years 9 months 18 days
Weighted-Average Remaining Contractual Term, Exercisable at June 30, 2022	8 years 3 months 18 days
Outstanding at June 30, 2022, Aggregate Intrinsic Value \| $	$ 31,456
Exercisable at March 31, 2022, Aggregate Intrinsic Value \| $	$ (7,637)

Share-based Compensation - Summary of The Black-Scholes Option Pricing Model to Estimate The Fair Value of Performance Stock Op (Details) - PSOs	9 Months Ended
	Sep. 30, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	3.37%
Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	3 years 5 months 1 day
Expected volatility	72.98%
Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	2 years 11 months 1 day
Expected volatility	72.72%

Share-based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	May 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock shares reserved for future issuance		10,354,341		10,354,341
Allocated share based compensation expense		$ 8,576	$ 5,149	$ 20,409	$ 8,224
IPO [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares issued upon conversion				5,433,290
PSOs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total fair value of options		1,200		$ 1,200
Share based compensation by share based payment arrangement non vested options granted during the period				152,550
Share based compensation by share based payment arrangement non vested options granted during the period weighted average grant date fair value				$ 7.78
Granted				152,550
PSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total fair value of options		1,500		$ 1,500
Weighted Average Grant Date Fair Value, Granted				$ 15.25
Number of Shares, Granted				99,250
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		65,700		$ 65,700
Share based compensation by share based payment arrangement unrecognized compensation remaining period for recognition				2 years 7 months 6 days
Unamortized stock-based compensation for stock options		6,400		$ 6,400
Weighted-average period expected to be recognized				3 years 4 months 24 days
Unvested PSOs and PSUs [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share based compensation by share based payment arrangement unrecognized compensation		2,700		$ 2,700
Incentive Share Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total fair value of options		15,600		$ 15,600
Share based compensation by share based payment arrangement non vested options granted during the period weighted average grant date fair value				$ 9.02
Share based compensation by share based payment arrangement unrecognized compensation remaining period for recognition				2 years 10 months 24 days
Unamortized stock-based compensation for stock options		$ 50,100		$ 50,100
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
2021 Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares issued upon conversion	4,719,605
Common stock shares reserved for future issuance	6,369,000
Share based compensation by share based payment arrangement non vested options granted during the period				2,868,380
Granted				2,868,380
2021 Equity Incentive Plan [Member] \| Incremental Shares Reserved for Future Issuance [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Percentage of Outstanding Stock Maximum	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		603,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Percentage of Outstanding Stock Maximum	1.00%
Allocated share based compensation expense		$ 17,000		$ 93,000
Stock Issued During Period, Shares, Employee Stock Ownership Plan				72,524

Share-based Compensation - Fair value of our common stock to be issued under the ESPP (Details) - 2021 Employee Stock Purchase Plan [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	6 months		6 months
Expected volatility	58.49%	0.00%	58.49%	0.00%
Risk-free interest rate	1.54%	0.00%	1.54%	0.00%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

Common Stock - Additional Information (Detail)	1 Months Ended		3 Months Ended		9 Months Ended
Common Stock - Additional Information (Detail)	Jun. 30, 2022 USD ($) $ / shares shares	Nov. 30, 2018 USD ($) shares	Sep. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) $ / shares shares	Sep. 30, 2021 USD ($)	Dec. 31, 2021 $ / shares shares
Class of Stock [Line Items]
Common Stock, Shares Authorized			500,000,000		500,000,000		500,000,000
Common Stock, Par or Stated Value Per Share \| $ / shares			$ 0.0001		$ 0.0001		$ 0.0001
Common Stock, Shares Issued			73,511,923		73,511,923		61,952,292
Common Stock, Shares Outstanding			73,511,923		73,511,923		61,952,292
Number of directors entitled to be elected by the holders of common stock		2
Stock Issued During Period, Value, New Issues \| $			$ 2,053,000	$ 167,045,000
Common stock shares reserved for future issuance			10,354,341		10,354,341
Proceeds from the issuance of common stock \| $					$ 161,610,000	$ 167,045,000
Common Shares Purchase Agreement [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized			500,000,000.0		500,000,000.0
Common Stock, Par or Stated Value Per Share \| $ / shares			$ 0.0001		$ 0.0001
Common Stock, Shares Issued			73,511,923		73,511,923
Sales Agreement with Piper Sandler and Jones Services LLC [Member]
Class of Stock [Line Items]
Common Stock, Par or Stated Value Per Share \| $ / shares	$ 15.00
Common Stock, Shares Issued	11,500,000
Common stock shares reserved for future issuance	1,500,000
Gross proceeds from issuance of common stock \| $	$ 150,000,000.0
Proceeds from the issuance of common stock \| $	$ 161,600,000
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

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares Issued	73,511,923	61,952,292
Common Stock, Shares Outstanding	73,511,923	61,952,292

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. These accounting principles were applied on a basis consistent with those of the consolidated financial statements contained in the Company's Annual Report on Form 10-K for the year ended December 31, 2021. In the opinion of the Company, the accompanying unaudited condensed consolidated financial statements include all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of our financial statements for interim periods presented in accordance with U.S. GAAP. The condensed consolidated balance sheet as of December 31, 2021 was derived from audited annual financial statements but does not include all disclosures required by U.S. GAAP. These interim financial statements should be read in conjunction with the audited financial statements for the year ended December 31, 2021 included in the Annual Report on Form 10-K for the year ended December 31, 2021. The results of operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year or any other future periods. The Company's significant accounting policies are described in Note 2 of the notes to the consolidated financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021. Updates to its accounting policies, including impacts from the adoption of new accounting standards, are discussed below in this Note 2. Because the Merger (refer to the section “Organization and Business”) did not constitute a change in the reporting entity, as defined in ASC 250, Accounting changes and error corrections, the Company has reported the assets and liabilities transferred from its Subsidiaries at historical carrying value, effective December 31, 2021. For further information, refer to the consolidated financial statements and footnotes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021. Any reference in these notes to applicable guidance is meant to refer to the authoritative generally accepted accounting principles as found in the Accounting Standards Codification, or ASC, and Accounting Standards Updates, or ASU, of the Financial Accounting Standards Board, or FASB.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. 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 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.
Concentration of credit risk and other risks and uncertainties	Concentration of credit risk and other risks and uncertainties Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents, and short-term investments. The Company’s cash, cash equivalents, and short-term investments are held in more than one financial institution in the United States. Amounts on deposit may at times exceed federally insured limits. Management believes that the financial institutions that the Company's cash, cash equivalents, and short-term investments are held at are financially sound and, accordingly, minimal credit risk exists with respect to the financial institutions. The Company is subject to certain risks and uncertainties and believes that changes in any of the following areas could have a material adverse effect on the Company's future financial position or results of its operations: ability to obtain future financing; regulatory requirements for approval and market acceptance of, and reimbursement for, product candidates; performance of third-party clinical research organizations and manufacturers upon which the Company relies; development of sales channels; protection of the Company’s intellectual property; litigation or claims against the Company based on intellectual property, patent, product, regulatory or other factors; changes to the market landscape; and the Company’s ability to attract and retain employees necessary to support its growth. The Company is dependent on third-party manufacturers to supply products for research and development activities in its programs. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the time of purchase to be cash equivalents. The Company’s cash equivalents consist of investments in money market funds and U.S. government agency securities. Cash equivalents are recognized at amortized cost, which approximates fair value.
Investments	Investments The Company’s investments are comprised of U.S. government agency securities and U.S. treasury securities. Investments are classified at the time of purchase, based on management’s intent, as held-to-maturity, available-for-sale, or trading. All of the Company’s investments are classified as available-for-sale. Available-for-sale securities are carried at estimated fair value with unrealized holdings gains and losses (net of tax effects) on such investments reported in other comprehensive (loss) income as a separate component on the condensed consolidated statements of comprehensive loss. Fair value is determined based on quoted market rates when observable or by utilizing data points that are observable, such as quoted prices, interest rates, and yield curves. For available-for-sale securities, the Company determines if any impairment is related to credit loss or non-credit loss. In making the assessment of whether a loss is from credit or other factors, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency and adverse conditions related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows is less than the amortized cost basis, a credit loss exists and an allowance is created, limited by the amount that the fair value is less than amortized cost basis. Subsequent activity related to the credit loss component in the form of write-offs or recoveries is recognized as part of the allowance for credit losses on available-for-sale securities.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Assets and liabilities recorded at fair value on a recurring basis in the condensed consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2—Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the asset or liability. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active; and Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The carrying amounts reflected in the accompanying condensed consolidated balance sheets for cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses and other current liabilities approximate their fair values, due to their short-term nature.
Emerging growth company status	Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. The JOBS Act does not preclude an emerging growth company from adopting a new or revised accounting standard earlier than the time that such standard applies to private companies. The Company expects to use the extended transition period for any other new or revised accounting standards during the period in which it remains an emerging growth company.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, or ASU 2019-12, which eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. ASU 2019-12 also clarifies and simplifies other aspects of the accounting for income taxes. The standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. The Company adopted ASU 2019-12 on January 1, 2022, and this adoption had no material impact on the Company’s financial statements and related disclosures.

Commitment and Contingencies - Additional Information (Detail)	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2022 USD ($) ft²	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Lessee, Lease, Description [Line Items]
Amortization of operating right-of-use assets				$ 303,000	$ 133,000
Weighted Average Remaining Lease Term		2 years		2 years
Weighted Average Discount Rate Percent		8.90%		8.90%
Research And Development Agreements
Lessee, Lease, Description [Line Items]
Termination and cancellation charges payable		$ 0		$ 0		$ 0
Viracta License Agreement
Lessee, Lease, Description [Line Items]
Royalty fee payable		0		0		0
Indemnification Agreement
Lessee, Lease, Description [Line Items]
Termination and cancellation charges payable		0		0		$ 0
Central America
Lessee, Lease, Description [Line Items]
Operating lease term	31 months
Sublease agreement area \| ft²	12,000
Operating lease payments	$ 1,100,000
Security Deposit	$ 40,000
Lease For Corporate Office Facility \| Central America
Lessee, Lease, Description [Line Items]
Tenant improvement allowances receivable		$ 10,000		$ 10,000
Lessee operating lease renewal lease term		3 years		3 years
Amortization of operating right-of-use assets		$ 100,000	$ 45,000	$ 300,000	100,000
Operating lease payments				$ 200,000	$ 200,000

Recurring Fair Value Measurement - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, measurement recurring basis, asset, transfers, net	$ 0	$ 0
Available-for-Sale Securities		0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 0	$ 0

Common Stock

9 Months Ended

Sep. 30, 2022

Stockholders' Equity Note [Abstract]

Common Stock

Pursuant to its certificate of incorporation, the Company is authorized to issue 500.0 million shares of common stock at a par value $0.0001. As of September 30, 2022, 73,511,923 shares of common stock were issued and outstanding.

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 vested monthly for two and four years, respectively. Vesting for a certain number of shares was accelerated upon the Company’s closing of its Series A redeemable convertible preferred share financing. The Company also has an option for a period of ninety days after the individual’s employment is terminated either voluntarily or involuntarily to repurchase the unvested common shares at a price that is the lower of the original price per share paid by the founder for such stock or the fair value as of the date of such repurchase. The founders’ shares were converted to common stock in the Conversion. As of September 30, 2022, all founders’ common stock were vested.

At-The-Market Offering

In June 2022, the Company entered into an equity distribution agreement with Piper Sandler & Co. and JonesTrading Institutional Services LLC, as sales agents, relating to the issuance and sale of shares of the Company’s common stock for an aggregate offering price of up to $150.0 million under an at-the-market offering program, or the 2022 ATM. During the nine months ended September 30, 2022, the Company did not make any sales under the 2022 ATM.

June 2022 Follow-On Offering

In June 2022, the Company completed a follow-on offering and issued and sold 11,500,000 shares of common stock (including the exercise by the underwriters of their option to purchase an additional 1,500,000 shares of common stock) at a price to the public of $15.00 per share for net proceeds of approximately $161.6 million, after deducting underwriting discounts, commissions, and offering costs.

The Company has reserved shares of common stock for future issuances as follows:


	September 30, 2022
Common stock options issued and outstanding		7,447,808
Common stock available for future grants		1,320,965
Common stock available for ESPP		1,149,998
Restricted stock units issued and outstanding		435,570
Total		10,354,341

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-URI https://asc.fasb.org/topic&trid=2208762

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496171-112644

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496171-112644

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI https://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496189-112644

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496189-112644

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496171-112644

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496189-112644

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496180-112644

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126731327&loc=SL126733271-114008

+ Details

Condensed Consolidated Statements of Redeemable Convertible Preferred Shares, Redeemable Noncontrolling Interest and Stockholders' Equity/ Members' (Deficit) (Parenthetical) (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2021
Common Stock [Member]
Stock issuance costs	$ 10,864	$ 16,995
Series B redeemable convertible preferred shares [Member]
Stock issuance costs			$ 243

Redeemable Convertible Preferred Shares

9 Months Ended

Sep. 30, 2022

Temporary Equity Disclosure [Abstract]

Redeemable Convertible Preferred Shares

On June 1, 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. As of September 30, 2022, 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.

Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2022

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 September 30,						Nine Months Ended September 30,
	2022			2021			2022			2021
Net loss	$	(37,795	)	$	(19,240	)	$	(102,072	)	$	(50,816	)
Net loss attributable to redeemable convertible noncontrolling interests		—			—			—			(2,109	)
Exchange of redeemable noncontrolling interest shares – deemed dividend		—			—			—			(99,994	)
Net loss attributable to common stockholders/members		(37,795	)		(19,240	)		(102,072	)		(148,701	)
Net loss per share, basic and diluted	$	(0.53	)	$	(0.33	)	$	(1.61	)	$	(4.98	)
Weighted-average number of common shares used in computing net loss per share, basic and diluted		71,008,993			57,514,218			63,522,774			29,859,883

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 September 30,
	2022		2021
Stock options		7,447,808		4,888,996
Unvested common shares		2,240,702		4,081,216
Restricted stock units		435,570		66,420
Performance stock units		99,250		—
Performance stock options		152,550		—
Shares committed under ESPP		51,169		—
Total		10,427,049		9,036,632

Recurring Fair Value Measurement - Schedule of available-for-sale marketable securities with gross unrealized losses (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Cash and Cash Equivalents [Line Items]
Unrealized Losses Less Than 12 Months, Fair value	$ 243,489
Unrealized Losses Less Than 12 Months, Unrealized losses	(393)
Unrealized losses	(393)
Fair Value	243,489
US Treasury Securities [Member]
Cash and Cash Equivalents [Line Items]
Unrealized Losses Less Than 12 Months, Fair value	218,452
Unrealized Losses Less Than 12 Months, Unrealized losses	(363)
Unrealized losses	(363)
Fair Value	218,452
U.S. government agency securities [Member]
Cash and Cash Equivalents [Line Items]
Unrealized Losses Less Than 12 Months, Fair value	25,037
Unrealized Losses Less Than 12 Months, Unrealized losses	(30)
Unrealized losses	(30)
Fair Value	$ 25,037

Share-based Compensation - Summary of The Black-Scholes Option Pricing Model to Estimate The Fair Value of Stock Option Granted (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Maximum [Member] \| Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	6 years 3 months 29 days	6 years 29 days	6 years 3 months 29 days	6 years 29 days
Expected volatility	70.71%	65.38%	70.71%	66.51%
Risk-free interest rate	4.09%	0.99%	4.09%	1.00%
Minimum [Member] \| Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	5 years 3 months 7 days	5 years 9 months 7 days	5 years 3 months 7 days	5 years 3 months 10 days
Expected volatility	68.96%	64.88%	65.20%	64.88%
Risk-free interest rate	2.65%	0.82%	1.47%	0.82%
Two Thousand Twenty One Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	6 months		6 months
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

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					9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net loss	$ (37,795)			$ (19,240)		$ (102,072)	$ (50,816)
Net loss attributable to redeemable convertible noncontrolling interests	0			0		0	(2,109)
Exchange of redeemable noncontrolling interest shares - deemed dividend	0			0		0	(99,994)
Net loss attributable to common stockholders/members	$ (37,795)	$ (36,530)	$ (27,747)	$ (19,240)	$ (14,284)	$ (102,072)	$ (148,701)
Net loss per share, Basic	$ (0.53)			$ (0.33)		$ (1.61)	$ (4.98)
Net loss per share, Diluted	$ (0.53)			$ (0.33)		$ (1.61)	$ (4.98)
Weighted-average number of common shares used in computing net loss per share, basic	71,008,993			57,514,218		63,522,774	29,859,883
Weighted-average number of common shares used in computing net loss per share, Diluted	71,008,993			57,514,218		63,522,774	29,859,883

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-URI https://asc.fasb.org/extlink&oid=126732423&loc=SL123482106-238011

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22583-107794

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=126958026&loc=d3e1448-109256

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22595-107794

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126958026&loc=d3e1337-109256

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126732423&loc=SL123482106-238011

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 52
-URI https://asc.fasb.org/extlink&oid=128363288&loc=d3e4984-109258

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 15
-URI https://asc.fasb.org/extlink&oid=128363288&loc=d3e3842-109258

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22644-107794

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126958026&loc=d3e1252-109256

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126958026&loc=SL5780133-109256

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 52
-URI https://asc.fasb.org/extlink&oid=128363288&loc=d3e4984-109258

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22644-107794

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 15
-URI https://asc.fasb.org/extlink&oid=128363288&loc=d3e3842-109258

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126958026&loc=d3e1252-109256

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22595-107794

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22583-107794

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126958026&loc=SL5780133-109256

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126732423&loc=SL123482106-238011

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126958026&loc=d3e1337-109256

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-URI https://asc.fasb.org/extlink&oid=126732423&loc=SL123482106-238011

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

+ Details

- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22595-107794

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=126958026&loc=d3e1448-109256

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 11
-URI https://asc.fasb.org/extlink&oid=126958026&loc=d3e1377-109256

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126958026&loc=SL5780133-109256

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 10: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8924-108599

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22583-107794

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

+ Details

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126968391&loc=SL7669619-108580

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22663-107794

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126732423&loc=SL123482106-238011

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 50
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=124431353&loc=SL124452729-227067

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3000-108585

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI https://asc.fasb.org/extlink&oid=126929396&loc=SL4569616-111683

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=109222650&loc=SL51721683-107760

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22499-107794

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=123596393&loc=d3e14064-108612

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-URI https://asc.fasb.org/extlink&oid=120399901&loc=d3e537907-122884

Reference 23: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8924-108599

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1B
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126968391&loc=SL7669625-108580

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 29: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(1)
-URI https://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684

Reference 31: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 55
-Paragraph 4J
-URI https://asc.fasb.org/extlink&oid=120409616&loc=SL4591551-111686

Reference 32: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 55
-Paragraph 4K
-URI https://asc.fasb.org/extlink&oid=120409616&loc=SL4591552-111686

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22658-107794

+ Details

Net Loss Per Share - Summary of Outstanding Potentially Dilutive Securities Have Been Excluded From Calculation of Diluted Net Loss Per Share (Detail) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	10,427,049	9,036,632
Share-based Payment Arrangement, Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	7,447,808	4,888,996
Unvested common shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	2,240,702	4,081,216
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	435,570	66,420
Shares committed under ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	51,169	0
Performance Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	99,250	0
Performance Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	152,550	0

Balance Sheet Items - Summary of Accrued expenses and other current liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued research and development expenses	$ 6,810	$ 3,308
Accrued payroll related expenses	5,046	2,565
Accrued professional service expenses	1,527	732
Other	453	104
Total accrued expenses and other current liabilities	$ 13,836	$ 6,709

Share-based Compensation - Summary of The Unvested Common Stock (Detail) - 2021 Stock Incentive Plan [Member]	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Unvasted Common Stock, Beginning balance \| shares	3,753,862
Vested \| shares	(1,341,702)
Forfeiture \| shares	(171,458)
Number of Shares, Unvasted Common Stock, Ending balance \| shares	2,240,702
Weighted Average Grant Date Fair Value Per Share, Beginning Balance	$ 16.00
Vested	16.00
Forfeiture	16.00
Weighted Average Grant Date Fair Value Per Share, Ending Balance	$ 16.00
Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vested \| shares	(51,030)
Weighted Average Grant Date Fair Value Per Share, Beginning Balance	$ 22.93
Vested	15.23
Forfeiture	14.11
Weighted Average Grant Date Fair Value Per Share, Ending Balance	$ 16.38

Common Stock - Schedule of Common Stock Shares Reserved for Future Issuance (Details) (Details)	Sep. 30, 2022 shares
Class of Stock [Line Items]
Common stock shares reserved for future issuance	10,354,341
Share-based Payment Arrangement, Option
Class of Stock [Line Items]
Common stock shares reserved for future issuance	1,320,965
Restricted Stock Units (RSUs) [Member]
Class of Stock [Line Items]
Common stock shares reserved for future issuance	435,570
Employee Stock Purchase Plan [Member]
Class of Stock [Line Items]
Common stock shares reserved for future issuance	1,149,998
Common Stock [Member]
Class of Stock [Line Items]
Common stock shares reserved for future issuance	7,447,808

Common Stock (Tables)

9 Months Ended

Sep. 30, 2022

Stockholders' Equity Note [Abstract]

Schedule of Common Stock Shares Reserved for Future Issuance

The Company has reserved shares of common stock for future issuances as follows:


	September 30, 2022
Common stock options issued and outstanding		7,447,808
Common stock available for future grants		1,320,965
Common stock available for ESPP		1,149,998
Restricted stock units issued and outstanding		435,570
Total		10,354,341

Recurring Fair Value Measurement - Schedule of cash equivalents, marketable securities, and unrealized gains and losses (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Line Items]
Cash equivalents, amortized cost	$ 120,864	$ 284,309
Marketable securities [Member]
Cash and Cash Equivalents [Line Items]
Debt securities, available-for-sale, amortized cost	253,869
Debt securities, available-for-sale, unrealized Gain	1
Debt securities, available-for-sale, unrealized loss	(393)
Debt securities, available-for-sale, estimated fair value	253,477
Cash equivalents [Member]
Cash and Cash Equivalents [Line Items]
Cash equivalents, amortized cost	106,403	111,221
Cash equivalents, unrealized gains	0	0
Cash equivalents, unrealized losses	0	0
Cash and cash equivalents, fair value disclosure	106,403	111,221
Money market funds [Member]
Cash and Cash Equivalents [Line Items]
Cash equivalents, amortized cost	34,081	111,221
Cash equivalents, unrealized gains	0	0
Cash equivalents, unrealized losses	0	0
Cash and cash equivalents, fair value disclosure	34,081	$ 111,221
U.S. government agency securities [Member]
Cash and Cash Equivalents [Line Items]
Cash equivalents, amortized cost	72,322
Cash equivalents, unrealized gains	0
Cash equivalents, unrealized losses	0
Cash and cash equivalents, fair value disclosure	72,322
Debt securities, available-for-sale, amortized cost	25,067
Debt securities, available-for-sale, unrealized Gain	0
Debt securities, available-for-sale, unrealized loss	(30)
Debt securities, available-for-sale, estimated fair value	25,037
U.S. treasury securities [Member]
Cash and Cash Equivalents [Line Items]
Debt securities, available-for-sale, amortized cost	228,802
Debt securities, available-for-sale, unrealized Gain	1
Debt securities, available-for-sale, unrealized loss	(363)
Debt securities, available-for-sale, estimated fair value	$ 228,440

Defined Contribution Plan	9 Months Ended
Defined Contribution Plan	Sep. 30, 2022
Retirement Benefits [Abstract]
Defined Contribution Plan	12. Defined Contribution Plan The Company maintains an employee savings plan pursuant to Section 401(k) of the Internal Revenue Code. All employees are eligible to participate provided that they meet the requirements of the plan. For the three and nine months ended September 30, 2022, the Company made matching contributions of $0.3 million and $0.8 million, respectively. The Company did not make matching contributions in the periods of the prior year.

Balance Sheet Items

9 Months Ended

Sep. 30, 2022

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Items

Prepaid Expenses and Other Current Assets

Prepaid and other current assets consisted of the following (in thousands):


	September 30, 2022		December 31, 2021
Prepaid research and development expenses	$	2,767	$	2,099
Prepaid insurance		2,459		1,945
Other prepaid expenses and other assets		946		1,015
Total prepaid expenses and other current assets	$	6,172	$	5,059

Property and Equipment, Net

Property and equipment, net, consisted of the following (in thousands):


	September 30, 2022			December 31, 2021
Furniture and fixtures	$	78		$	78
Leasehold improvements		40			15
Property and equipment, gross		118			93
Less: accumulated depreciation		(83	)		(36	)
Property and equipment, net	$	35		$	57

Depreciation expense for each of the three and nine months ended September 30, 2022 and 2021 was immaterial.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	September 30, 2022		December 31, 2021
Accrued research and development expenses	$	6,810	$	3,308
Accrued payroll related expenses		5,046		2,565
Accrued professional service expenses		1,527		732
Other		453		104
Total accrued expenses and other current liabilities	$	13,836	$	6,709

Balance Sheet Items - Summary of Prepaid and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid research and development expenses	$ 2,767	$ 2,099
Prepaid insurance	2,459	1,945
Other prepaid expenses and other assets	946	1,015
Total prepaid expenses and other current assets	$ 6,172	$ 5,059

Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2022

Commitments and Contingencies Disclosure [Abstract]

Summary of Future Lease Obligations

As of September 30, 2022, the future lease obligations were as follows (in thousands):



Remaining in 2022	$	165
2023		476
2024		424
Total future minimum lease payments		1,065
Less: Imputed interest		89
Present value of operating lease liabilities	$	976

Share-based Compensation (Tables)

9 Months Ended

Sep. 30, 2022

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:


		Nine Months Ended September 30,
		2021
Common share fair value		$6.36 - $8.89
Participating threshold		$6.36 - $7.51
Risk free rate		0.14%
Volatility		72.90%
Time to liquidity (in years)		0.20 - 1.80
Grant date fair value		$4.24 - $4.52

Summary of The Unvested Common Stock

The following table provides a summary of the unvested common stock awards activity during the nine months ended September 30, 2022.


	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Unvested common stock as of December 31, 2021		3,753,862		$	16.00
Vested		(1,341,702	)	$	16.00
Forfeiture		(171,458	)	$	16.00
Unvested common stock as of September 30, 2022		2,240,702		$	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 nine months ended September 30, 2022.


	Options			Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2021		5,071,896		$	16.90
Granted		2,868,380		$	14.81
Exercised		(130,899	)	$	15.95
Forfeiture		(361,569	)	$	15.09
Outstanding at September 30, 2022		7,447,808		$	16.20		8.8	$	31,456
Exercisable at September 30, 2022		1,927,895		$	16.35		8.3	$	7,637

Summary of Restricted Stock Units Activity Under the 2021 Plan

The following table provides a summary of restricted stock units activity under the 2021 Plan during the nine months ended September 30, 2022:


	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Unvested restricted stock units at December 31, 2021		96,890		$	22.93
Granted		417,995		$	14.57
Vested		(51,030	)	$	15.23
Forfeiture		(28,285	)	$	14.11
Unvested restricted stock units at September 30, 2022		435,570		$	16.38

Schedule of fair value of our common stock to be issued under the ESPP

The fair value of our common stock to be issued under the ESPP is estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions:


	Three Months Ended September 30,			Nine Months Ended September 30,
	2022	2021		2022	2021
Expected term (in years)	0.50		—	0.50		—
Expected volatility	58.49%		—	58.49%		—
Risk-free interest rate	1.54%		—	1.54%		—
Expected dividend yield	—		—	—		—

Summary of The Black-Scholes Option Pricing Model to Estimate The Fair Value of Performance Stock Option Granted

The Company used the Black-Scholes option pricing model to estimate the fair value of the PSO awards granted with the following assumptions:


	Nine Months Ended September 30,
	2022	2021
Expected term (in years)	2.92 - 3.42		—
Expected volatility	72.72% - 72.98%		—
Risk-free interest rate	3.37%		—
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 is as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Research and development expense	$	2,020	$	1,489	$	6,242	$	2,321
General and administrative expense		6,556		3,660		14,167		5,903
Total share-based compensation expense	$	8,576	$	5,149	$	20,409	$	8,224

Defined Contribution Plan (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Retirement Benefits [Abstract]
Matching Contribution	$ 0.3	$ 0.8

Balance Sheet Items (Tables)

9 Months Ended

Sep. 30, 2022

Balance Sheet Related Disclosures [Abstract]

Schedule of Prepaid and Other Current Assets

Prepaid and other current assets consisted of the following (in thousands):


	September 30, 2022		December 31, 2021
Prepaid research and development expenses	$	2,767	$	2,099
Prepaid insurance		2,459		1,945
Other prepaid expenses and other assets		946		1,015
Total prepaid expenses and other current assets	$	6,172	$	5,059

Schedule of Property and Equipment

Property and equipment, net, consisted of the following (in thousands):


	September 30, 2022			December 31, 2021
Furniture and fixtures	$	78		$	78
Leasehold improvements		40			15
Property and equipment, gross		118			93
Less: accumulated depreciation		(83	)		(36	)
Property and equipment, net	$	35		$	57

Schedule of Accrued expenses and other current liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	September 30, 2022		December 31, 2021
Accrued research and development expenses	$	6,810	$	3,308
Accrued payroll related expenses		5,046		2,565
Accrued professional service expenses		1,527		732
Other		453		104
Total accrued expenses and other current liabilities	$	13,836	$	6,709

Redeemable NonControlling Interest

9 Months Ended

Sep. 30, 2022

Temporary Equity Disclosure [Abstract]

Redeemable NonControlling Interest

11.

Redeemable Noncontrolling Interest

Prior to the Merger, DOT-1, the Company’s subsidiary, issued Series A redeemable convertible preferred shares to Takeda in accordance with the Takeda Asset Agreement (Note 5). The Company concluded that it represented a redeemable noncontrolling interest.

The Company adjusted the carrying value of redeemable noncontrolling interest to allocate net losses of the subsidiary to Takeda. Transfers to and from the redeemable noncontrolling interest represented 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 terms of the Millennium Stock Exchange Agreement, Takeda exchanged 9,857,143 shares of Series A redeemable convertible preferred stock in DOT-1 for 6,470,382 shares of common stock of the Company. Prior to the Exchange, the Company accounted for the redeemable noncontrolling interest as discussed in the paragraph above and allocated $1.2 million and $2.1 million of net losses for the period from April 1 to May 26, 2021 and from January 1 to May 26, 2021, respectively, to Takeda. The Exchange resulted in DOT-1 becoming a wholly owned subsidiary of the Company and was recorded for accounting purposes as an extinguishment of the redeemable noncontrolling interest. As such, the Company also recognized an extinguishment loss of $100.0 million to additional paid-in-capital, which was calculated as a difference between the fair value of common stock issued to Takeda in the conversion and the carrying value of redeemable noncontrolling interest at the conversion date. The all-stock exchange was treated as a deemed dividend in the calculation of net loss attributable to common stockholders/members and net loss and per share.

Share-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		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	$ 8,576	$ 5,149	$ 20,409	$ 8,224
Research and Development Expense [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	2,020	1,489	6,242	2,321
General and Administrative Expense [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	$ 6,556	$ 3,660	$ 14,167	$ 5,903

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets
Total assets	$ 381,861	$ 289,821
Current assets:
Cash and cash equivalents	120,864	284,309
Short-term investments	253,477	0
Prepaid expenses and other current assets	6,172	5,059
Total current assets	380,513	289,368
Property and equipment, net	35	57
Operating lease right-of-use asset	864	227
Deposits and other long-term assets	449	169
Liabilities and stockholders' equity
Total liabilities	18,785	8,673
Current Liabilities:
Total current liabilities	18,271	8,657
Accounts payable	3,973	1,744
Accrued expenses and other current liabilities	13,836	6,709
Current portion of operating lease liabilities	462	204
Long-term portion of lease liabilities	514	16
Commitments and contingencies (Note 6)
Stockholders' equity
Common stock, $0.0001 par value; 500,000,000 shares authorized as of September 30, 2022 and December 31, 2021; [ ] and 61,952,292 shares issued and outstanding as of September 30, 2022 and December 31, 2021, respectively	7	6
Additional paid-in-capital	593,020	408,629
Accumulated other comprehensive loss	(392)	0
Accumulated deficit	(229,559)	(127,487)
Total stockholders' equity	363,076	281,148
Total liabilities and stockholders' equity	$ 381,861	$ 289,821

Commitments and Contingencies

9 Months Ended

Sep. 30, 2022

Commitments and Contingencies Disclosure [Abstract]

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 January 2023. Such agreement was determined to be a lease since the right to control the use of the identified asset was conveyed to the Company for a period of time in exchange for consideration. 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 component and a variable consideration and included in operating expenses as incurred. The extension period has not been included in the determination of the Right of Use, or ROU, asset or the lease liability for operating leases as the Company concluded that it is not reasonably certain that it would exercise this option.

In April 2022, the Company entered into a lease agreement for approximately 12,000 square feet of general use office space in Brisbane, California. Such agreement was determined to be a lease since the right to control the use of the identified asset was conveyed to the Company for a period of time in exchange for consideration. The term of the lease is for 31 months and commenced in May 2022. There is no option to extend the lease term nor is there an option to terminate the lease term prior to its expiration. The Company is obligated to pay monthly rent expense and its pro rata share of the landlord's operating expenses which include utilities, common area maintenance expenses, and property taxes. Such expenses are a non-lease component and a variable consideration and included in the Company's operating expenses as incurred. The Company concluded that this lease is also an operating lease. The total payments for base rent over the term of the lease is approximately $1.1 million. Upon execution of the agreement, the Company paid a security deposit of approximately $40,000 classified as deposits and other long-term assets on the condensed consolidated balance sheet.

The Company determined the lease incremental borrowing rate, or IBR, based on the information available at the applicable lease commencement date as the Company’s leases do not 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. As of September 30, 2022, the weighted-average remaining lease term and weighted-average discount rate were 2.0 years and 8.9%, respectively.

The Company’s leases do not require any contingent rental payments, impose financial restrictions, or contain any residual value guarantees.

Lease expense of right-of-use assets is recognized on a straight-line basis over the applicable lease term. Lease expense was $0.1 million and $45,000 for the three months ended September 30, 2022 and 2021, respectively, and was $0.3 million and $0.1 million for the nine months ended September 30, 2022 and 2021, respectively. Cash paid for amounts included in the measurement of operating lease liabilities was $0.2 million for the nine months ended September 30, 2022 and 2021. Variable payments expensed during the three and nine months ended September 30, 2022 and 2021 were immaterial.

As of September 30, 2022, the future lease obligations were as follows (in thousands):



Remaining in 2022	$	165
2023		476
2024		424
Total future minimum lease payments		1,065
Less: Imputed interest		89
Present value of operating lease liabilities	$	976

Research and Development Agreements

The Company enters into contracts in the normal course of business with clinical research organizations, contract manufacturing organizations and other third-party vendors for clinical trial, manufacturing, testing, and other research and development activities. 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 another vendor where labor costs are non-cancellable after the approval of the project plan. As of September 30, 2022 and December 31, 2021, there were no amounts accrued related to termination and cancellation charges as these are not probable.

License Agreements

The Company entered into the license agreements, as disclosed in Note 5, 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 year ended December 31, 2021. The second milestone related to the MRKDG License Agreement was achieved and recorded to research and development during the nine months ended September 30, 2022. The Company may be required to pay royalties on sales of products developed under these agreements. All products are in development as of September 30, 2022 and December 31, 2021, and no 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 September 30, 2022 and December 31, 2021.

Recurring Fair Value Measurement (Tables)

9 Months Ended

Sep. 30, 2022

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

The following table sets forth the Company’s financial instruments as of September 30, 2022 and December 31, 2021, which are measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):


	September 30, 2022
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds	$	34,081	$	—	$	—	$	34,081
U.S. treasury securities		—		228,440		—		228,440
U.S. government agency securities		—		97,359		—		97,359
Total assets measured at fair value	$	34,081	$	325,799	$	—	$	359,880


	December 31, 2021
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds	$	111,221	$	—	$	—	$	111,221
Total assets measured at fair value	$	111,221	$	—	$	—	$	111,221

Schedule of cash equivalents, marketable securities, and unrealized gains and losses

The following tables summarize the estimated fair value of the Company's cash equivalents, available-for-sale securities classified as short-term investments, and associated unrealized gains and losses (in thousands):


	September 30, 2022
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Cash equivalents:
Money market funds	$	34,081	$	—	$	—		$	34,081
U.S. government agency securities		72,322		—		—			72,322
Total cash equivalents		106,403		—		—			106,403

Short-term investments
U.S. treasury securities		228,802		1		(363	)		228,440
U.S. government agency securities		25,067		—		(30	)		25,037
Total short-term investments	$	253,869	$	1	$	(393	)	$	253,477


	December 31, 2021
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Cash equivalents:
Money market funds	$	111,221	$	—	$	—	$	111,221
Total cash equivalents	$	111,221	$	—	$	—	$	111,221

Schedule of available-for-sale marketable securities with gross unrealized losses

The following table presents the breakdown of the Company's available-for-sale securities with gross unrealized losses and the duration that those losses had been unrealized as September 30, 2022 (in thousands):


	September 30, 2022
	Unrealized Losses Less Than 12 Months					Unrealized Losses 12 Months or Greater				Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Financial assets:
U.S. treasury securities	$	218,452	$	(363	)	$	—	$	—	$	218,452	$	(363	)
U.S. government agency securities		25,037		(30	)		—		—		25,037		(30	)
Total financial assets	$	243,489	$	(393	)	$	—	$	—	$	243,489	$	(393	)

Schedule of maturities of our available-for-sale marketable securities table text block

The following table summarizes the maturities of our cash equivalents and available-for-sale securities as of September 30, 2022 (in thousands):


	Amortized Cost		Fair Value
Mature in one year or less	$	360,272	$	359,880
Total	$	360,272	$	359,880

Redeemable NonControlling Interest - Additional Information (Detail) - USD ($) $ in Thousands		2 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended
	May 26, 2021	May 26, 2021	Sep. 30, 2022	Sep. 30, 2021	May 26, 2021	Sep. 30, 2022	Sep. 30, 2021
Redeemable Noncontrolling Interest [Line Items]
Net loss attributable to redeemable noncontrolling interests			$ 0	$ 0		$ 0	$ (2,109)
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 noncontrolling interests		$ 1,200			$ 2,100

Description of Business and Organization - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	9 Months Ended
	Jun. 01, 2021	May 23, 2021	Jun. 30, 2021	Sep. 30, 2022	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from issuance of initial public offering	$ 167,000
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	500,000,000
Preferred stock shares authorized				10,000,000
Common stock par or stated value per share				$ 0.0001	$ 0.0001
Preferred stock par or stated value per share				$ 0.0001
Stockholders' equity note, stock split		2.325-for-1
Retained Earnings (Accumulated Deficit)				$ (229,559)	$ (127,487)
Cash equivalents, amortized cost				$ 120,864	$ 284,309
IPO [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock issued in IPO, net of issuance costs of $16,995 (In shares)	11,500,000		11,500,000
Shares issued, price per share	$ 16.00			$ 16.00
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

Significant Agreements - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 16, 2019	Feb. 28, 2021	Sep. 30, 2022	Jun. 30, 2021	Sep. 30, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock Issued During Period, Value, New Issues			$ 2,053	$ 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
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]
Issuance of Series B redeemable convertible preferred shares for cash, net of issuance costs, shares	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
Issuance of Series B redeemable convertible preferred shares for cash, net of issuance costs, shares	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
Merck License Agreement [Member] \| Research and Development Expense [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of Milestones					2,500
Merck License Agreement [Member] \| Research and Development Expense [Member] \| Maximum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of Milestones					$ 364,500
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

Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2022	Nov. 02, 2022
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
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	Yes
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	2000 Sierra Point Parkway
Entity Address, Address Line Two	Suite 501
Entity Address, City or Town	Brisbane
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94005
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		73,549,526

Condensed Consolidated Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating expenses:
Research and development	$ 22,035	$ 9,849	$ 59,598	$ 32,395
General and administrative	17,664	9,392	44,568	18,373
Total operating expenses	39,699	19,241	104,166	50,768
Loss from operations	(39,699)	(19,241)	(104,166)	(50,768)
Interest income (expense), net	1,895	(6)	2,086	(19)
Other income (expense), net	9	7	8	(29)
Net loss	(37,795)	(19,240)	(102,072)	(50,816)
Net loss attributable to redeemable noncontrolling interests	0	0	0	(2,109)
Exchange of redeemable noncontrolling interest shares-deemed dividend	0	0	0	(99,994)
Net loss attributable to common stockholders/members	$ (37,795)	$ (19,240)	$ (102,072)	$ (148,701)
Net loss per share, Basic	$ (0.53)	$ (0.33)	$ (1.61)	$ (4.98)
Net loss per share, Diluted	$ (0.53)	$ (0.33)	$ (1.61)	$ (4.98)
Weighted-average number of common shares used in computing net loss per share, basic	71,008,993	57,514,218	63,522,774	29,859,883
Weighted-average number of common shares used in computing net loss per share, Diluted	71,008,993	57,514,218	63,522,774	29,859,883

Commitment and Contingencies - Summary of Future Lease Obligations (Detail) $ in Thousands	Sep. 30, 2022 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining in 2022	$ 165
2023	476
2024	424
Total future minimum lease payments	1,065
Less: Imputed interest	89
Present value of operating lease liabilities	$ 976

Summary Of Significant Accounting Policies	9 Months Ended
Summary Of Significant Accounting Policies	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. These accounting principles were applied on a basis consistent with those of the consolidated financial statements contained in the Company's Annual Report on Form 10-K for the year ended December 31, 2021. In the opinion of the Company, the accompanying unaudited condensed consolidated financial statements include all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of our financial statements for interim periods presented in accordance with U.S. GAAP. The condensed consolidated balance sheet as of December 31, 2021 was derived from audited annual financial statements but does not include all disclosures required by U.S. GAAP. These interim financial statements should be read in conjunction with the audited financial statements for the year ended December 31, 2021 included in the Annual Report on Form 10-K for the year ended December 31, 2021. The results of operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year or any other future periods. The Company's significant accounting policies are described in Note 2 of the notes to the consolidated financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021. Updates to its accounting policies, including impacts from the adoption of new accounting standards, are discussed below in this Note 2. Because the Merger (refer to the section “Organization and Business”) did not constitute a change in the reporting entity, as defined in ASC 250, Accounting changes and error corrections, the Company has reported the assets and liabilities transferred from its Subsidiaries at historical carrying value, effective December 31, 2021. For further information, refer to the consolidated financial statements and footnotes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021. Any reference in these notes to applicable guidance is meant to refer to the authoritative generally accepted accounting principles as found in the Accounting Standards Codification, or ASC, and Accounting Standards Updates, or ASU, of the Financial Accounting Standards Board, or FASB. Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. 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 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. Concentration of credit risk and other risks and uncertainties Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents, and short-term investments. The Company’s cash, cash equivalents, and short-term investments are held in more than one financial institution in the United States. Amounts on deposit may at times exceed federally insured limits. Management believes that the financial institutions that the Company's cash, cash equivalents, and short-term investments are held at are financially sound and, accordingly, minimal credit risk exists with respect to the financial institutions. The Company is subject to certain risks and uncertainties and believes that changes in any of the following areas could have a material adverse effect on the Company's future financial position or results of its operations: ability to obtain future financing; regulatory requirements for approval and market acceptance of, and reimbursement for, product candidates; performance of third-party clinical research organizations and manufacturers upon which the Company relies; development of sales channels; protection of the Company’s intellectual property; litigation or claims against the Company based on intellectual property, patent, product, regulatory or other factors; changes to the market landscape; and the Company’s ability to attract and retain employees necessary to support its growth. The Company is dependent on third-party manufacturers to supply products for research and development activities in its programs. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the time of purchase to be cash equivalents. The Company’s cash equivalents consist of investments in money market funds and U.S. government agency securities. Cash equivalents are recognized at amortized cost, which approximates fair value. Investments The Company’s investments are comprised of U.S. government agency securities and U.S. treasury securities. Investments are classified at the time of purchase, based on management’s intent, as held-to-maturity, available-for-sale, or trading. All of the Company’s investments are classified as available-for-sale. Available-for-sale securities are carried at estimated fair value with unrealized holdings gains and losses (net of tax effects) on such investments reported in other comprehensive (loss) income as a separate component on the condensed consolidated statements of comprehensive loss. Fair value is determined based on quoted market rates when observable or by utilizing data points that are observable, such as quoted prices, interest rates, and yield curves. For available-for-sale securities, the Company determines if any impairment is related to credit loss or non-credit loss. In making the assessment of whether a loss is from credit or other factors, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency and adverse conditions related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows is less than the amortized cost basis, a credit loss exists and an allowance is created, limited by the amount that the fair value is less than amortized cost basis. Subsequent activity related to the credit loss component in the form of write-offs or recoveries is recognized as part of the allowance for credit losses on available-for-sale securities. Fair Value of Financial Instruments Assets and liabilities recorded at fair value on a recurring basis in the condensed consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2—Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the asset or liability. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active; and Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The carrying amounts reflected in the accompanying condensed consolidated balance sheets for cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses and other current liabilities approximate their fair values, due to their short-term nature. Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. The JOBS Act does not preclude an emerging growth company from adopting a new or revised accounting standard earlier than the time that such standard applies to private companies. The Company expects to use the extended transition period for any other new or revised accounting standards during the period in which it remains an emerging growth company. Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, or ASU 2019-12, which eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. ASU 2019-12 also clarifies and simplifies other aspects of the accounting for income taxes. The standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. The Company adopted ASU 2019-12 on January 1, 2022, and this adoption had no material impact on the Company’s financial statements and related disclosures.

Description of Business and Organization

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description of Business and Organization

Organization and Business

Day One Biopharmaceuticals, Inc., or the Company, is a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for patients of all ages with life-threatening diseases. The Company was formed as a limited liability company under the laws of the State of Delaware in November 2018, under the name Hero Therapeutics Holding Company, LLC. Subsequently, the Company changed its name to Day One Therapeutics Holding Company, LLC in December 2018 and to Day One Biopharmaceuticals Holding Company, LLC, or Day One Holding LLC, in March 2020.

On May 26, 2021, the Company completed a 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. Prior to December 31, 2021, the Company had two subsidiaries: DOT Therapeutics-2, Inc. (formerly Hero Therapeutics Inc. and Day One Biopharmaceuticals, Inc.), or DOT-2, incorporated in Delaware in November 2018, and DOT Therapeutics-1, Inc., or DOT-1, incorporated in Delaware in December 2019. DOT-2 and DOT-1 are collectively referred to herein as the Subsidiaries.

In December 2021, the Company’s board of directors approved the merger, or the Merger, of the Subsidiaries with and into the Company, with the Company being the surviving corporation, effective December 31, 2021. For more information on the financial statement impact of the Merger, refer to the section titled “Basis of Presentation.”

Initial Public Offering, Corporate Conversion and Exchange of Takeda’s shares

On June 1, 2021, the Company closed its initial public offering, or 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 a legal entity conversion, or the Conversion, which included the following: Day One Holding LLC (i) 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 (ii) 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 participating threshold for each incentive share. The Company issued 5,433,290 common stock shares upon the conversion of incentive shares of Day One Holding LLC, of which 4,719,605 common stock shares continue to vest as per the original vesting terms of the incentive shares awards.

In connection with the IPO and the Conversion, pursuant to the terms of the Millennium Stock Exchange Agreement, or the Millennium Stock Exchange Agreement, and the Conversion, Millennium Pharmaceuticals, Inc. exchanged 9,857,143 shares of Series A redeemable convertible preferred stock of DOT-1, a subsidiary of Day One Holding LLC, for 6,470,382 shares of common stock of the Company, or the Exchange.

The Company holds all property and assets of Day One Holding LLC and assumed all of the debts and obligations of Day One Holding LLC. Effective on the date of the Conversion, each member of the board of directors and officers of Day One Holding LLC became a member of the board of directors and officers of the Company. The Conversion was a tax-free reorganization, that included authorization to issue capital stock consisting of 500,000,000 shares of common stock, $0.0001 par value per share, and 10,000,000 shares of undesignated preferred stock, $0.0001 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, the board of directors of Day One Holding LLC approved an amendment to its operating agreement to effect a forward split of the Company’s shares at a 2.325-for-1 ratio, or 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.

Share-based Compensation - Summary of Restricted Stock Units Activity (Detail) - Two Thousand And Twenty One Stock Incentive Plan [Member]	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vested \| shares	(1,341,702)
Weighted Average Grant Date Fair Value Per Share, Beginning Balance	$ 16.00
Vested	16.00
Weighted Average Grant Date Fair Value, Forfeited	16.00
Weighted Average Grant Date Fair Value Per Share, Ending Balance	$ 16.00
Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unvested restricted stock at December 31, 2021 \| shares	96,890
Granted \| shares	417,995
Vested \| shares	(51,030)
Forfeiture \| shares	(28,285)
Unvested restricted stock at June 30, 2022 \| shares	435,570
Weighted Average Grant Date Fair Value Per Share, Beginning Balance	$ 22.93
Grant date fair value	14.57
Vested	15.23
Weighted Average Grant Date Fair Value, Forfeited	14.11
Weighted Average Grant Date Fair Value Per Share, Ending Balance	$ 16.38

Net Loss Per Share

9 Months Ended

Sep. 30, 2022

Earnings Per Share [Abstract]

Net Loss Per Share

10.

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 September 30,						Nine Months Ended September 30,
	2022			2021			2022			2021
Net loss	$	(37,795	)	$	(19,240	)	$	(102,072	)	$	(50,816	)
Net loss attributable to redeemable convertible noncontrolling interests		—			—			—			(2,109	)
Exchange of redeemable noncontrolling interest shares – deemed dividend		—			—			—			(99,994	)
Net loss attributable to common stockholders/members		(37,795	)		(19,240	)		(102,072	)		(148,701	)
Net loss per share, basic and diluted	$	(0.53	)	$	(0.33	)	$	(1.61	)	$	(4.98	)
Weighted-average number of common shares used in computing net loss per share, basic and diluted		71,008,993			57,514,218			63,522,774			29,859,883

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 September 30,
	2022		2021
Stock options		7,447,808		4,888,996
Unvested common shares		2,240,702		4,081,216
Restricted stock units		435,570		66,420
Performance stock units		99,250		—
Performance stock options		152,550		—
Shares committed under ESPP		51,169		—
Total		10,427,049		9,036,632

Redeemable Convertible Preferred Shares - Additional Information (Detail) - USD ($)		1 Months Ended
	Jun. 01, 2021	Jun. 30, 2021	Feb. 28, 2021	Sep. 30, 2022
Temporary Equity [Line Items]
Payment of stock issuance costs	$ 17,000,000.0
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 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			$ 130,000,000.0

Significant Agreements

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Significant Agreements

License agreement with Merck KGaA, Darmstadt, Germany

On February 10, 2021, DOT-2, the Company’s subsidiary, entered into a license agreement, or 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 for the Company to research, develop, manufacture, and commercialize products containing and comprising the pimasertib and MSC2015103B compounds. The Company also received clinical inventories supplies to use in its research and development activities. The Company’s exclusive license grant is subject to a non-exclusive license granted by Merck KGaA, Darmstadt, Germany’s affiliate to a cancer research organization and Merck KGaA, Darmstadt, Germany retains the right to conduct, directly or indirectly, certain ongoing clinical studies relating to pimasertib.

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. Additionally, the Company made a milestone payment of $2.5 million, which was recorded as research and development expenses due to the nature of the license agreement and the milestone event relating to the first dosing of a patient in a first clinical trial of a product containing pimasertib, in the nine months ended September 30, 2022. The Company may also be required to make additional payments of up to $364.5 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.

The term of the MRKDG License Agreement will expire on a licensed product-by-licensed product and country-by-country basis upon the expiration of the Company’s obligation to pay royalties to the licensor with respect to such licensed product in such country and will expire in its entirety upon the expiration of all of the Company’s payment obligations with respect to all licensed products and all countries under the MRKDG License Agreement.

Effective December 31, 2021, DOT-2 was merged with and into the Company, with the Company being the surviving corporation and assuming DOT-2’s obligations under the MRKDG License Agreement.

Takeda Assets Purchase Agreement

On December 16, 2019, DOT-1 entered into an asset purchase agreement, or the Takeda Asset Agreement, with Millennium Pharmaceuticals, Inc., a related party and an affiliate of Takeda Pharmaceutical Company Limited, or Takeda. Pursuant to the Takeda Asset Agreement, DOT-1 purchased certain technology rights and know-how related to TAK-580 (which is now tovorafenib (DAY101)) that provides a new approach for treating patients with primary brain tumors or brain metastases of solid tumors. DOT-1 also received clinical inventories supplies to use in the Company’s research and development activities of such RAF-inhibitor and an assigned investigator clinical trial agreement. Takeda also assigned to DOT-1 its exclusive license agreement, or the Viracta License Agreement, with Viracta Therapeutics, Inc. (f/k/a Sunesis Pharmaceuticals, Inc.), or Viracta. Takeda also granted DOT-1 a worldwide, sublicensable exclusive license under specified patents and know-how and non-exclusive license under other patents and know-how generated by Takeda under the Takeda Asset Agreement. The Company also granted Takeda a grant back license, as defined in the Takeda Asset Agreement, which is terminable either automatically or by DOT-1 in the event Takeda does not achieve specified development milestones within the applicable timeframes set forth under the Takeda Asset Agreement. This grant back license to Takeda was terminated at the time of Conversion in connection with the Millennium Stock Exchange Agreement.

In consideration for the sale and assignment of assets and the grant of the license under the Takeda Asset Agreement, DOT-1 made an upfront payment of $1.0 million in cash and issued 9,857,143 shares of Series A redeemable convertible preferred stock in DOT-1 in December 2019. The fair value of issued shares was estimated as $9.9 million, based on the price paid by other investors for issued shares in the Series A financing of DOT-1. Based on the terms of the Millennium Stock Exchange Agreement, Takeda exchanged the 9,857,143 shares of Series A redeemable convertible preferred stock of DOT-1 for 6,470,382 shares of the Company’s common stock upon the effectiveness of the Conversion, on May 26, 2021.

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 the Company's 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 in the event of the Company's 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.

Effective December 31, 2021, DOT-1 was merged with and into the Company, with the Company being the surviving corporation and assuming DOT-1’s obligations under the Takeda Assets Purchase Agreement.

Viracta License Agreement

On December 16, 2019, DOT-1 amended and restated the Viracta License Agreement that was assigned pursuant to the Takeda Asset Agreement. Under the Viracta License Agreement, DOT-1 received a worldwide exclusive license under specified patent rights and know-how to develop, use, manufacture, and commercialize products containing compounds binding the RAF protein family.

DOT-1 paid $2.0 million upfront in cash to Viracta, which was recorded as research and development expenses in 2019. DOT-1 made a milestone payment of $3.0 million to Viracta in February 2021, which was recorded as research and development expense when the milestone was achieved in April 2021. DOT-1 is also required to make additional milestone payments of up to $54.0 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 obtains a priority review voucher with respect to a licensed product and sells such priority review voucher to a third party or uses such priority review voucher, DOT-1 is obligated to pay Viracta a specified percentage in the mid-teen digits of all net consideration received from any such sale or of the value of such used priority review voucher, as applicable. Commencing on the first commercial sale of a licensed product in a country, DOT-1 is obligated to pay tiered royalties ranging in the mid-single-digit percentages on net sales of licensed products, if any. The obligation to pay royalties will end on a country-by-country and licensed product-by-licensed product basis commencing on the first commercial sale in a country and continuing until the later of: (i) the expiration of the last valid claim of the Viracta licensed patents, jointly owned collaboration patents or specified patents owned by the Company covering the use or sale of such product in such country, (ii) the expiration of the last statutory exclusivity pertaining to such product in such country or (iii) the tenth anniversary of the first commercial sale of such product in such country. No other milestones, except as discussed above, were achieved and due as of September 30, 2022.

The term of the Viracta License Agreement will expire on a licensed product-by-licensed product and country-by-country basis upon the expiration of the Company’s obligation to pay royalties to Viracta with respect to such product in such country.

DOT-1 has the right to terminate the Viracta License Agreement with respect to any or all of the licensed products at will upon a specified notice period.

Effective December 31, 2021, DOT-1 was merged with and into the Company, with the Company being the surviving corporation and assuming DOT-1’s obligations under Viracta License Agreement.

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities
Net loss	$ (102,072)	$ (50,816)
Adjustments to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development assets	0	8,000
Share-based compensation expense	20,409	8,224
Depreciation expense	48	15
Accretion of discounts on debt securities	(1,031)	0
Amortization of operating right-of-use assets	303	133
Non-cash interest expense	0	19
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,113)	(4,808)
Deposits and other long-term assets	(280)	(31)
Accounts payable	2,229	483
Accrued expenses and other current liabilities	7,127	3,565
Operating lease liabilities	(184)	(154)
Net cash used in operating activities	(74,564)	(35,370)
Cash flows from investing activities
Cash paid for acquired in-process research and development assets	0	(8,000)
Cash paid for purchase of short-term investments	(272,838)	0
Proceeds from maturity of short-term investments	20,000	0
Cash paid for purchase of property and equipment	(26)	0
Cash used in investing activities	(252,864)	(8,000)
Cash flows from financing activities
Proceeds from issuance of Series B redeemable convertible preferred shares, net of issuance costs	0	129,757
Proceeds from issuance of common stock, net	161,610	167,045
Proceeds from issuance of common stock upon stock option exercises	2,053	0
Proceeds from issuance of common stock upon ESPP purchase	320	0
Net cash provided by financing activities	163,983	296,802
Net increase in cash and cash equivalents	(163,445)	253,432
Cash and cash equivalents, beginning of period	284,309	43,728
Cash and cash equivalents, end of period	120,864	297,160
Supplemental disclosures of noncash activities
Lease liability obtained in exchange for right-of-use asset	940	0
Exchange of 45,331,483 preferred, common, and incentive shares in connection with the Conversion (Note 1)	0	224,892
Exchange of redeemable convertible noncontrolling interest to 6,470,382 shares of common stock (Note 11)	$ 0	$ 3,592

Condensed Consolidated Statements of Redeemable Convertible Preferred Shares, Redeemable Noncontrolling Interest and Stockholders' Equity/ Members' (Deficit) (unaudited) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock [Member]	Redeemable Noncontrolling Interest [Member]	Common Stock [Member]	Common Stock [Member] Redeemable Convertible Preferred Stock [Member]	Common Stock [Member] Redeemable Noncontrolling Interest [Member]	Common Shares [Member]	Incentive Shares	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2020	$ (54,205)				$ 91,964	$ 5,702	$ 2,000	$ 637		$ (56,842)
Beginning Balance (In shares) at Dec. 31, 2020		22,851,257					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, shares		9,638,141
Net loss attributable to redeemable 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	$ 2,000	$ 1,175		(72,024)
Ending Balance (In shares) at Mar. 31, 2021		32,489,398					6,035,869	4,986,352
Beginning Balance at Dec. 31, 2020	(54,205)				91,964	5,702	$ 2,000	$ 637		(56,842)
Beginning Balance (In shares) at Dec. 31, 2020		22,851,257					6,035,869	4,112,012
Unrealized loss on available-for-sale securities	0
Net loss attributable to redeemable noncontrolling interests	(2,109)
Net loss attributable to common stockholders/members	(148,701)
Ending Balance at Sep. 30, 2021	297,672			$ 6					$ 403,214	(105,548)
Ending Balance (In shares) at Sep. 30, 2021				61,928,939
Beginning Balance at Mar. 31, 2021	(68,849)				$ 221,721	$ 4,783	$ 2,000	$ 1,175		(72,024)
Beginning Balance (In shares) at Mar. 31, 2021		32,489,398					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
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 stockholders/members	(14,284)									(14,284)
Ending Balance at Jun. 30, 2021	311,763			$ 6					398,065	(86,308)
Ending Balance (In shares) at Jun. 30, 2021				61,928,939
Share-based compensation expenses	5,149								5,149
Unrealized loss on available-for-sale securities	0
Net loss attributable to redeemable noncontrolling interests	0
Net loss attributable to common stockholders/members	(19,240)									(19,240)
Ending Balance at Sep. 30, 2021	297,672			$ 6					403,214	(105,548)
Ending Balance (In shares) at Sep. 30, 2021				61,928,939
Beginning Balance at Dec. 31, 2021	281,148						$ 6		408,629	(127,487)
Beginning Balance (In shares) at Dec. 31, 2021							61,952,292
Share-based compensation expenses	6,202								6,202
Unvested stock forfeiture							(40,363)
Net loss attributable to common stockholders/members	(27,747)									(27,747)
Ending Balance at Mar. 31, 2022	259,603						$ 6		414,831	(155,234)
Ending Balance (In shares) at Mar. 31, 2022							61,911,929
Beginning Balance at Dec. 31, 2021	281,148						$ 6		408,629	(127,487)
Beginning Balance (In shares) at Dec. 31, 2021							61,952,292
Unrealized loss on available-for-sale securities	(392)
Net loss attributable to redeemable noncontrolling interests	0
Net loss attributable to common stockholders/members	(102,072)
Ending Balance at Sep. 30, 2022	363,076						$ 7		593,020	(229,559)	$ (392)
Ending Balance (In shares) at Sep. 30, 2022							73,511,923
Beginning Balance at Mar. 31, 2022	259,603						$ 6		414,831	(155,234)
Beginning Balance (In shares) at Mar. 31, 2022							61,911,929
Share-based compensation expenses	5,631								5,631
Unrealized loss on available-for-sale securities	(3)										(3)
Issuance of common stock pursuant to follow-on offering, net of issuance costs, Shares							11,500,000
Issuance of common stock pursuant to follow-on offering, net of issuance costs, Amount	161,610						$ 1		161,609
Issuance of common stock pursuant to Employee Stock Purchase Plan, Shares							49,171
Issuance of common stock pursuant to Employee Stock Purchase Plan, Amount	320								320
Net loss attributable to common stockholders/members	(36,530)									(36,530)
Ending Balance at Jun. 30, 2022	390,631						$ 7		582,391	(191,764)	(3)
Ending Balance (In shares) at Jun. 30, 2022							73,461,100
Share-based compensation expenses	8,576								8,576
Unrealized loss on available-for-sale securities	(389)										(389)
Issuance of Series B redeemable convertible preferred shares for cash, net of issuance costs, shares							130,899
Net loss attributable to redeemable noncontrolling interests	0
Issuance of common stock pursuant to follow-on offering, net of issuance costs, Amount									2,053
Conversion of redeemable convertible preferred, common, and incentive shares into common stock (In shares)							51,030
Common stock issued in IPO, net of issuance costs of $16,995	2,053
Unvested stock forfeiture							(131,106)
Net loss attributable to common stockholders/members	(37,795)									(37,795)
Ending Balance at Sep. 30, 2022	$ 363,076						$ 7		$ 593,020	$ (229,559)	$ (392)
Ending Balance (In shares) at Sep. 30, 2022							73,511,923

Recurring Fair Value Measurements

9 Months Ended

Sep. 30, 2022

Fair Value Disclosures [Abstract]

Recurring Fair Value Measurements


	September 30, 2022
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds	$	34,081	$	—	$	—	$	34,081
U.S. treasury securities		—		228,440		—		228,440
U.S. government agency securities		—		97,359		—		97,359
Total assets measured at fair value	$	34,081	$	325,799	$	—	$	359,880


	December 31, 2021
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds	$	111,221	$	—	$	—	$	111,221
Total assets measured at fair value	$	111,221	$	—	$	—	$	111,221

The Company's money market funds are classified as Level 1 because they are measured using observable inputs from active markets for identical assets.

The Company's U.S. treasury securities and U.S. government agency securities are classified as Level 2 because they are measured with inputs that are either directly or indirectly observable for the asset which include quoted prices for similar assets in active markets and quoted prices for identical or similar assets in markets that are not active.

There were no assets or liabilities classified as Level 3 as of September 30, 2022 and December 31, 2021.

There were no transfers between Level 1, Level 2 or Level 3 categories during the periods presented.


	September 30, 2022
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Cash equivalents:
Money market funds	$	34,081	$	—	$	—		$	34,081
U.S. government agency securities		72,322		—		—			72,322
Total cash equivalents		106,403		—		—			106,403

Short-term investments
U.S. treasury securities		228,802		1		(363	)		228,440
U.S. government agency securities		25,067		—		(30	)		25,037
Total short-term investments	$	253,869	$	1	$	(393	)	$	253,477


	December 31, 2021
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Cash equivalents:
Money market funds	$	111,221	$	—	$	—	$	111,221
Total cash equivalents	$	111,221	$	—	$	—	$	111,221

The following table summarizes the maturities of our cash equivalents and available-for-sale securities as of September 30, 2022 (in thousands):


	Amortized Cost		Fair Value
Mature in one year or less	$	360,272	$	359,880
Total	$	360,272	$	359,880


	September 30, 2022
	Unrealized Losses Less Than 12 Months					Unrealized Losses 12 Months or Greater				Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Financial assets:
U.S. treasury securities	$	218,452	$	(363	)	$	—	$	—	$	218,452	$	(363	)
U.S. government agency securities		25,037		(30	)		—		—		25,037		(30	)
Total financial assets	$	243,489	$	(393	)	$	—	$	—	$	243,489	$	(393	)

The Company did not have available-for-sale securities with gross unrealized losses as of December 31, 2021.

The Company regularly reviews the changes to the rating of its securities and monitors the surrounding economic conditions to assess the risk of expected credit losses. As of September 30, 2022 and December 31, 2021, there were no securities that were in an unrealized loss position for more than 12 months. As of September 30, 2022, the unrealized losses on the Company’s investments in U.S. treasury securities and U.S. government securities were caused by interest rate increases. The current credit ratings are all within the guidelines of the investment policy of the Company and the Company does not expect the issuers to settle any security at a price less than the amortized cost basis of the investment with the contractual cash flows of these investments guaranteed by the issuer. No allowance for credit losses has been recorded since it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Share-based Compensation

9 Months Ended

Sep. 30, 2022

Stockholders' Equity Note [Abstract]

Share-based Compensation

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 class of shares that participated in distributions only after incentive shares vested, unless it was approved by the board of directors and included at least two of the preferred members, and a participation threshold was met. The incentive shares represented profits interests in Day One Holding LLC, which was an interest in the increase in the Company’s value over the participation threshold, as defined in its operating agreement and as determined at the time of grant. A holder of incentive shares had the right to participate in distributions of profits only in excess of the participation threshold. The participation threshold was based on the valuation of the Company’s common shares on or around the grant date.

The fair value of the incentive shares was estimated using an option pricing model with the following assumptions:


		Nine Months Ended September 30,
		2021
Common share fair value		$6.36 - $8.89
Participating threshold		$6.36 - $7.51
Risk free rate		0.14%
Volatility		72.90%
Time to liquidity (in years)		0.20 - 1.80
Grant date fair value		$4.24 - $4.52

During the Conversion, the Company converted all incentive shares to vested and unvested shares of common stock. As such, there was no incentive shares activity for the nine months ended September 30, 2022.

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 were determined by the board of directors 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.

2021 Equity Incentive Plan

Immediately prior to consummation of the IPO, all the outstanding incentive shares were converted into common stock. The following table provides a summary of the unvested common stock awards activity during the nine months ended September 30, 2022.


	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Unvested common stock as of December 31, 2021		3,753,862		$	16.00
Vested		(1,341,702	)	$	16.00
Forfeiture		(171,458	)	$	16.00
Unvested common stock as of September 30, 2022		2,240,702		$	16.00

In May 2021, in connection with the IPO, the board of directors and stockholders approved the 2021 Equity Incentive Plan, or 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, non-statutory 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: (x) 6,369,000 shares of common stock; plus (y) 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 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) 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 following table provides a summary of stock option activity under the 2021 Plan during the nine months ended September 30, 2022.


	Options			Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2021		5,071,896		$	16.90
Granted		2,868,380		$	14.81
Exercised		(130,899	)	$	15.95
Forfeiture		(361,569	)	$	15.09
Outstanding at September 30, 2022		7,447,808		$	16.20		8.8	$	31,456
Exercisable at September 30, 2022		1,927,895		$	16.35		8.3	$	7,637

Aggregate intrinsic value represents the difference between the estimated fair value of the underlying common stock and the exercise price of outstanding, in-the-money options.

The total fair value of options that vested during the nine months ended September 30, 2022 was $15.6 million. The weighted-average grant date fair value of options granted during the nine months ended September 30, 2022 was $9.02 per share.

Unamortized stock-based compensation for stock options as of September 30, 2022 was $50.1 million, which is expected to be recognized over a weighted-average period of 2.9 years.

The Company used the Black-Scholes option pricing model to estimate the fair value of stock options awards granted with the following assumptions:


	Three Months Ended September 30,			Nine Months Ended September 30,
	2022	2021		2022	2021
Expected term (in years)	5.27 - 6.33	5.77 - 6.08		5.27 - 6.33	5.28 - 6.08
Expected volatility	68.96% - 70.71%	64.88% - 65.38%		65.20% - 70.71%	64.88% - 66.51%
Risk-free interest rate	2.65% - 4.09%	0.82% - 0.99%		1.47% - 4.09%	0.82% - 1.00%
Expected dividend yield	—		—	—		—

The following table provides a summary of restricted stock units activity under the 2021 Plan during the nine months ended September 30, 2022:


	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Unvested restricted stock units at December 31, 2021		96,890		$	22.93
Granted		417,995		$	14.57
Vested		(51,030	)	$	15.23
Forfeiture		(28,285	)	$	14.11
Unvested restricted stock units at September 30, 2022		435,570		$	16.38

Unamortized stock-based compensation for restricted stock units as of September 30, 2022 was $6.4 million, which is expected to be recognized over a weighted-average period of 3.4 years.

2021 Employee Stock Purchase Plan

In May 2021, the board of directors adopted, and the stockholders approved the 2021 Employee Stock Purchase Plan, or the ESPP, which became effective on May 26, 2021. A total of 603,000 shares of common stock were initially 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) and (b) an amount determined by the board of directors. 72,524 shares have been issued under the ESPP as of September 30, 2022. The Company recognized approximately $17,000 and approximately $93,000 compensation expense related to the ESPP plan for the three and nine months ending September 30, 2022.

The fair value of our common stock to be issued under the ESPP is estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions:


	Three Months Ended September 30,			Nine Months Ended September 30,
	2022	2021		2022	2021
Expected term (in years)	0.50		—	0.50		—
Expected volatility	58.49%		—	58.49%		—
Risk-free interest rate	1.54%		—	1.54%		—
Expected dividend yield	—		—	—		—

Performance Awards

In June 2022, the Company granted performance awards, consisting of performance stock options, or PSOs, and performance stock units, or PSUs, to non-executive employees pursuant to the 2021 Equity Incentive Plan. Each performance award is earned through the achievement of a performance-based metric over a defined performance period determined by the compensation committee of the Company's board of directors. The estimated fair value of the equity awards that contain performance conditions is expensed over the term of the award once the Company has determined that it is probable that the performance conditions will be satisfied. During the nine months ended September 30, 2022, the Company granted 152,550 PSOs with a weighted-average grant date fair value of $7.78 per share and 99,250 PSUs with a weighted-average grant date fair value of $15.25 per share. The total fair values of PSOs and PSUs granted were $1.2 million and $1.5 million, respectively. As of September 30, 2022, no PSOs or PSUs had vested since the achievement of the performance-based metrics of the performance awards was not deemed probable.

The Company used the Black-Scholes option pricing model to estimate the fair value of the PSO awards granted with the following assumptions:


	Nine Months Ended September 30,
	2022	2021
Expected term (in years)	2.92 - 3.42		—
Expected volatility	72.72% - 72.98%		—
Risk-free interest rate	3.37%		—
Expected dividend yield	—		—

Share/stock-based compensation expense recorded in the accompanying condensed consolidated statements of operations is as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Research and development expense	$	2,020	$	1,489	$	6,242	$	2,321
General and administrative expense		6,556		3,660		14,167		5,903
Total share-based compensation expense	$	8,576	$	5,149	$	20,409	$	8,224

As of September 30, 2022, there was $65.7 million of unrecognized compensation cost related to unvested restricted stock, unvested restricted stock units, unvested stock options, and shares subject to purchase under the ESPP that is expected to be recognized over a weighted-average period of approximately 2.6 years.

As of September 30, 2022, there was $2.7 million of unrecognized compensation cost related to unvested PSOs and PSUs. The Company will recognize the PSO and PSU expense through the expected vesting dates when the achievement of the performance-based metrics is probable.

Recurring Fair Value Measurement - Schedule of maturities of available-for-sale marketable securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Line Items]
Amortized cost, Mature in one year or less	$ 360,272
Amortized Cost, Total	360,272
Fair value		$ 0
Fair Value, Mature in one year or less	359,880
Fair Value, Total	$ 359,880

Condensed Consolidated Statements of Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net loss	$ (37,795)	$ (19,240)	$ (102,072)	$ (50,816)
Other comprehensive loss:
Unrealized loss on available-for-sale securities	(389)	0	(392)	0
Total comprehensive loss	$ (38,184)	$ (19,240)	$ (102,464)	$ (50,816)

- Definition

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

+ References

+ Details

Balance Sheet Items - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 118	$ 93
Less: accumulated depreciation	(83)	(36)
Property, and equipment, net	35	57
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	78	78
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 40	$ 15

Recurring Fair Value Measurement - Summary of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
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	$ 34,081	$ 111,221
U.S. government agency securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	72,322
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	359,880	111,221
Fair Value, Recurring [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	34,081	111,221
Fair Value, Recurring [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	325,799	0
Fair Value, Recurring [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	0	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	34,081	111,221
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	34,081	111,221
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	0	0
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	0	$ 0
Fair Value, Recurring [Member] \| U.S. treasury securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	228,440
Fair Value, Recurring [Member] \| U.S. treasury securities [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	0
Fair Value, Recurring [Member] \| U.S. treasury securities [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	228,440
Fair Value, Recurring [Member] \| U.S. treasury securities [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	0
Fair Value, Recurring [Member] \| U.S. government agency securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	97,359
Fair Value, Recurring [Member] \| U.S. government agency securities [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	0
Fair Value, Recurring [Member] \| U.S. government agency securities [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	97,359
Fair Value, Recurring [Member] \| U.S. government agency securities [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	$ 0