0000950170-22-009734 | 10-Q | XBRL Viewer | DAY ONE Biopharmaceuticals INC

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Equity-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
	Mar. 31, 2022	Mar. 31, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	$ 6,202	$ 538
Research and Development Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	2,147	119
General and Administrative Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	$ 4,055	$ 419

Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 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 March 31, 2022 and December 31, 2021, which are measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):


	March 31, 2022
	Total		Level 1		Level 2		Level 3
Money market funds, included in cash and cash equivalents	$	90,265	$	90,265	$	—	$	—


	December 31, 2021
	Total		Level 1		Level 2		Level 3
Money market funds, included in cash and cash equivalents	$	111,221	$	111,221	$	—	$	—

Common Stock - Schedule of Common Stock Shares Reserved for Future Issuance (Details) (Details)	Mar. 31, 2022 shares
Class of Stock [Line Items]
Common stock shares reserved for future issuance	10,692,078
Share-based Payment Arrangement, Option
Class of Stock [Line Items]
Common stock shares reserved for future issuance	2,081,924
Restricted Stock Units (RSUs) [Member]
Class of Stock [Line Items]
Common stock shares reserved for future issuance	392,757
Employee Stock Purchase Plan [Member]
Class of Stock [Line Items]
Common stock shares reserved for future issuance	1,199,169
Common Stock [Member]
Class of Stock [Line Items]
Common stock shares reserved for future issuance	7,018,228

Commitment and Contingencies - Summary of Future Lease Obligations (Detail) $ in Thousands	Mar. 31, 2022 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining in 2022	$ 158
2023	18
Total future minimum lease payments	176
Less: Imputed interest	(5)
Present value of operating lease liabilities	$ 171

Equity-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	3 Months Ended
	Mar. 31, 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	2,008,230
Forfeiture \| shares	(61,898)
Number of Shares, Ending Balance \| shares	7,018,228
Exercisable at March 31, 2022 \| shares	293,995
Weighted Average Exercise Price, Beginning Balance \| $ / shares	$ 16.90
Granted \| $ / shares	14.22
Forfeiture \| $ / shares	16.78
Weighted Average Exercise Price, Ending Balance \| $ / shares	16.13
Exercisable at March 31, 2022 \| $ / shares	$ 15.91
Weighted-Average Remaining Contractual Term, Outstanding at March 31, 2022	9 years 3 months 18 days
Weighted-Average Remaining Contractual Term, Exercisable at March 31, 2022	9 years 2 months 12 days
Outstanding at March 31, 2022, Aggregate Intrinsic Value \| $	$ 26
Exercisable at March 31, 2022, Aggregate Intrinsic Value \| $	$ 0

Common Stock

3 Months Ended

Mar. 31, 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 March 31, 2022, 61,911,929 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 March 31, 2022, all founders’ common stock were vested.

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


	March 31, 2022
Common stock options issued and outstanding		7,018,228
Common stock available for future grants		2,081,924
Common stock available for ESPP		1,199,169
Restricted stock units issued and outstanding		392,757
Total		10,692,078

- 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

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Redeemable NonControlling Interest

3 Months Ended

Mar. 31, 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 $0.9 million and $2.1 million of net losses for the period from January 1 to March 31, 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.

Net Loss Per Share

3 Months Ended

Mar. 31, 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 March 31,
	2022			2021
Net loss and comprehensive loss	$	(27,747	)	$	(16,101	)
Net loss attributable to redeemable convertible noncontrolling interests		—			(919	)
Net loss attributable to common stockholders/members		(27,747	)		(15,182	)
Net loss per share, basic and diluted	$	(0.48	)	$	(2.58	)
Weighted-average number of common shares used in computing net loss per share, basic and diluted		58,382,444			5,892,145

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 March 31,
	2022		2021
Stock options		7,018,228		—
Unvested common shares		3,352,683		48,456
Restricted stock units		392,757		—
Shares committed under ESPP		24,357		—
Redeemable convertible preferred shares		—		32,489,398
Incentive Shares		—		4,986,352
Total		10,788,025		37,524,206

Significant Agreements - Additional Information (Detail) - USD ($) $ in Millions		1 Months Ended	3 Months Ended
	Dec. 16, 2019	Feb. 28, 2021	Mar. 31, 2022
Takeda Asset Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront of cash payment	$ 1.0
Takeda Asset Agreement [Member] \| Common Stock [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Issuance of Series A redeemable convertible preferred shares, 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	$ 9.9
Issuance of Series A redeemable convertible preferred shares, shares	9,857,143
Takeda Asset Agreement [Member] \| Research and Development Expense [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment			$ 8.0
Merck License Agreement [Member] \| Research and Development Expense [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of Milestones			$ 367.0
Viracta License Agreement [Member] \| Maximum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of Milestones		$ 54.0
Viracta License Agreement [Member] \| Research and Development Expense [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of Milestones		$ 3.0
Upfront of cash payment	$ 2.0

Equity-Based Compensation (Tables)

3 Months Ended

Mar. 31, 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:


		Three Months Ended March 31,
		2021
Common share fair value		$6.36 - $7.51
Participating threshold		$6.36
Risk free rate		0.14%
Volatility		72.90%
Time to liquidity (in years)		0.20 - 1.80
Grant date fair value		$4.52

Summary of The Unvested Common Stock

The following table provides a summary of the unvested common stock awards activity during the three months ended March 31, 2022.


	Number of Shares			Weighted Average Grant Date Fair Value
Unvested common stock as of December 31, 2021		3,753,862		$	16.00
Vested		(360,816	)	$	16.00
Forfeiture		(40,363	)	$	16.00
Unvested common stock as of March 31, 2022		3,352,683		$	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 three months ended March 31, 2022.


	Options			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2021		5,071,896		$	16.90
Granted		2,008,230		$	14.22
Forfeiture		(61,898	)	$	16.78
Outstanding at March 31, 2022		7,018,228		$	16.13		9.3	$	26
Exercisable at March 31, 2022		293,995		$	15.91		9.2	$	—

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 three months ended March 31, 2022:


	Number of Shares			Weighted Average Grant Date Fair Value
Unvested restricted stock units at December 31, 2021		96,890		$	22.93
Granted		311,945		$	14.21
Vested		(14,068	)	$	14.26
Forfeiture		(2,010	)	$	19.88
Unvested restricted stock units at March 31, 2022		392,757		$	16.33

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

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 March 31, 2022
	Stock Options
Expected term (in years)	5.90 - 6.08
Expected volatility	65.20% - 66.92%
Risk-free interest rate	1.47% - 2.55%
Expected dividend yield		—

Summary of Share/Stock-based Compensation Expense Recorded in The Accompanying Condensed Consolidated Statements of Operations and Comprehensive Loss

Share/stock-based compensation expense recorded in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Loss is as follows (in thousands):


	Three Months Ended March 31,
	2022		2021
Research and development expense	$	2,147	$	119
General and administrative expense		4,055		419
Total share-based compensation expense	$	6,202	$	538

Balance Sheet Items - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 107	$ 93
Less: accumulated depreciation	(41)	(36)
Property, and equipment, net	66	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	14	15
Other Property and Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 15	$ 0

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Preferred Stock, Par or Stated Value Per Share	$ 0.0001
Preferred Stock, Shares Authorized	10,000,000
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	61,911,929	61,952,292
Common Stock, Shares Outstanding	61,911,929	61,952,292

Net Loss Per Share - Summary of Outstanding Potentially Dilutive Securities Have Been Excluded From Calculation of Diluted Net Loss Per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	10,788,025	37,524,206
Share-based Payment Arrangement, Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	7,018,228	0
Unvested common shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	3,352,683	48,456
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	392,757	0
Shares committed under ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	24,357	0
Redeemable convertible preferred shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	0	32,489,398
Incentive Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options	0	4,986,352

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

Common Stock (Tables)

3 Months Ended

Mar. 31, 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:


	March 31, 2022
Common stock options issued and outstanding		7,018,228
Common stock available for future grants		2,081,924
Common stock available for ESPP		1,199,169
Restricted stock units issued and outstanding		392,757
Total		10,692,078

Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 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 March 31,
	2022			2021
Net loss and comprehensive loss	$	(27,747	)	$	(16,101	)
Net loss attributable to redeemable convertible noncontrolling interests		—			(919	)
Net loss attributable to common stockholders/members		(27,747	)		(15,182	)
Net loss per share, basic and diluted	$	(0.48	)	$	(2.58	)
Weighted-average number of common shares used in computing net loss per share, basic and diluted		58,382,444			5,892,145

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 March 31,
	2022		2021
Stock options		7,018,228		—
Unvested common shares		3,352,683		48,456
Restricted stock units		392,757		—
Shares committed under ESPP		24,357		—
Redeemable convertible preferred shares		—		32,489,398
Incentive Shares		—		4,986,352
Total		10,788,025		37,524,206

Commitments and Contingencies

3 Months Ended

Mar. 31, 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. 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.

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 lease did 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. The Company determined the amounts of its lease liabilities using an IBR of 8%. As of March 31, 2022, the remaining lease term was 0.8 years.

The Company’s lease does 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 $47,000 and $44,000 for the three months ended March 31, 2022 and 2021, respectively. Cash paid for amounts included in the measurement of operating lease liabilities was $52,000 and $51,000 for the three months ended March 31, 2022 and 2021, respectively. Variable payments expensed during the three months ended March 31, 2022 and 2021 were immaterial.

As of March 31, 2022, the future lease obligations were as follows (in thousands):


For the Years Ending December 31,	March 31, 2022
Remaining in 2022	$	158
2023		18
Total future minimum lease payments		176
Less: Imputed interest		(5	)
Present value of operating lease liabilities	$	171

Research and Development Agreements

The Company enters into contracts in the normal course of business with clinical research organizations for clinical trials, with contract manufacturing organizations for clinical supplies manufacturing and with other vendors for preclinical studies, supplies and other services and products for operating purposes. These contracts generally provide for termination on notice, with the exception of one vendor with a potential termination fee if a purchase order is cancelled within a specified time, and another vendor where labor costs are non-cancellable after the approval of the project plan. As of March 31, 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 Company may be required to pay royalties on sales of products developed under these agreements. All products are in development as of March 31, 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 March 31, 2022 and December 31, 2021.

Equity-Based Compensation - Summary of Restricted Stock Units Activity (Detail) - Two Thousand And Twenty One Stock Incentive Plan [Member]	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested \| shares	(360,816)
Weighted Average Grant Date Fair Value, Beginning Balance	$ 16.00
Vested	16.00
Weighted Average Grant Date Fair Value, Forfeited	16.00
Weighted Average Grant Date Fair Value, 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	311,945
Vested \| shares	(14,068)
Forfeiture \| shares	(2,010)
Unvested restricted stock at March 31, 2022 \| shares	392,757
Weighted Average Grant Date Fair Value, Beginning Balance	$ 22.93
Grant date fair value	14.21
Vested	14.26
Weighted Average Grant Date Fair Value, Forfeited	19.88
Weighted Average Grant Date Fair Value, Ending Balance	$ 16.33

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 262,731	$ 284,309
Prepaid expenses and other current assets	4,637	5,059
Total current assets	267,368	289,368
Property and equipment, net	66	57
Operating lease right-of-use asset	180	227
Deposits and other long-term assets	165	169
Total assets	267,779	289,821
Current liabilities:
Accounts payable	701	1,744
Accrued expenses and other current liabilities	7,304	6,709
Current portion of operating lease liabilities	171	204
Total current liabilities	8,176	8,657
Operating lease liabilities, long-term	0	16
Total liabilities	8,176	8,673
Commitments and contingencies (Note 6)
Stockholders' equity/members' (deficit)
Common stock, $0.0001 par value; 500,000,000 shares authorized as of March 31, 2022 and December 31, 2021; 61,952,292 shares issued and outstanding as of March 31, 2022 and December 31, 2021	6	6
Additional paid-in-capital	414,831	408,629
Accumulated deficit	(155,234)	(127,487)
Total stockholders' equity	259,603	281,148
Total liabilities and stockholders' equity	$ 267,779	$ 289,821

Balance Sheet Items - Summary of Prepaid and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid insurance	$ 874	$ 2,099
Prepaid research and development expenses	3,365	1,945
Other prepaid expenses and other assets	398	1,015
Total prepaid expenses and other current assets	$ 4,637	$ 5,059

Subsequent Event	3 Months Ended
Subsequent Event	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Event	13. Subsequent Event On April 1, 2022, the Company entered into a lease agreement for approximately 12,000 square feet of general use office space in Brisbane, California. The initial term of the lease is for 31 months and commences in May 2022. The total payments for base rent over the term of the lease is approximately $1.1 million. Additionally, the Company is required to pay a security deposit of approximately $40,000 upon execution of the sublease agreement.

Fair Value Measurements

3 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Fair Value Measurements

The financial instruments of the Company measured at fair value on a recurring basis are U.S. government money market funds, recorded as cash equivalents. The fair value is based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy.


	March 31, 2022
	Total		Level 1		Level 2		Level 3
Money market funds, included in cash and cash equivalents	$	90,265	$	90,265	$	—	$	—


	December 31, 2021
	Total		Level 1		Level 2		Level 3
Money market funds, included in cash and cash equivalents	$	111,221	$	111,221	$	—	$	—

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

- 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

Equity-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	May 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance		10,692,078
Allocated share based compensation expense		$ 6,202	$ 538
ESPP awards		$ 0
IPO [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares issued upon conversion		5,433,290
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		$ 70,900
Share based compensation by share based payment arrangement unrecognized compensation remaining period for recognition		3 years 1 month 6 days
Unamortized stock-based compensation for stock options		$ 6,000
Weighted-average period expected to be recognized		3 years 8 months 12 days
Incentive Share Plan [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
Total fair value of options		$ 1,700
Share based compensation by share based payment arrangement non vested options granted during the period weighted average grant date fair value		$ 8.47
Unamortized stock-based compensation for stock options		$ 53,000
Weighted-average period expected to be recognized		3 years 3 months 18 days
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		2,008,230
2021 Equity Incentive Plan [Member] \| Unvested Restricted Stock and Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement term of vesting		4 years
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
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum	1.00%
Allocated share based compensation expense		$ 100
Stock Issued During Period, Shares, Employee Stock Ownership Plan		23,353

Significant Agreements

3 Months Ended

Mar. 31, 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. The Company may also be required to make additional payments of up to $367.0 million based upon the achievement of specified development, regulatory, and commercial milestones, as well a high, single-digit royalty percentage on future net sales of licensed products, if any. Milestones and royalties are contingent upon future events and will be recorded when the milestones are achieved and when payments are due. No milestones were achieved and due as of March 31, 2022.

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 March 31, 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.

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
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Net loss and comprehensive loss	$ (27,747)	$ (16,101)
Net loss attributable to redeemable convertible noncontrolling interests	0	(919)
Net loss attributable to common stockholders/members	$ (27,747)	$ (15,182)
Net loss per share, basic and diluted	$ (0.48)	$ (2.58)
Weighted-average number of common shares used in computing net loss per share, basic and diluted	58,382,444	5,892,145

- Definition

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

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+ Details

Balance Sheet Items (Tables)

3 Months Ended

Mar. 31, 2022

Balance Sheet Related Disclosures [Abstract]

Schedule of Prepaid and Other Current Assets

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


	March 31, 2022		December 31, 2021
Prepaid insurance	$	874	$	2,099
Prepaid research and development expenses		3,365		1,945
Other prepaid expenses and other assets		398		1,015
Total prepaid expenses and other current assets	$	4,637	$	5,059

Schedule of Property and Equipment

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


	March 31, 2022			December 31, 2021
Furniture and fixtures	$	78		$	78
Leasehold improvements		14			15
Other property and equipment		15			—
Property and equipment, gross		107			93
Less: accumulated depreciation		(41	)		(36	)
Property and equipment, net	$	66		$	57

Schedule of Accrued expenses and other current liabilities

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


	March 31, 2022		December 31, 2021
Accrued payroll related expenses	$	1,648	$	3,308
Accrued research and development expenses		4,171		2,565
Accrued professional service expenses		1,098		732
Other		387		104
Total accrued expenses and other current liabilities	$	7,304	$	6,709

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (27,747)	$ (16,101)
Adjustments to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development assets		8,000
Share-based compensation expense	6,202	538
Depreciation expense	6	5
Amortization of operating right-of-use assets	47	44
Non-cash interest expense		7
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	422	(2,542)
Deposits and other long-term assets	4	(26)
Accounts payable	(1,043)	484
Accrued expenses and other current liabilities	595	(101)
Operating lease liabilities	(49)	(51)
Net cash used in operating activities	(21,563)	(9,743)
Cash flows from investing activities
Cash paid for acquired in-process research and development assets		(8,000)
Property and equipment expenditures	(15)
Cash used in investing activities	(15)	(8,000)
Cash flows from financing activities
Proceeds from issuance of Series B redeemable convertible preferred shares, net of issuance costs		129,757
Payments of financing issuance costs		(872)
Net cash provided by financing activities		128,885
Net increase (decrease) in cash and cash equivalents	(21,578)	111,142
Cash and cash equivalents, beginning of period	284,309	43,728
Cash and cash equivalents, end of period	262,731	154,870
Supplemental disclosures of noncash activities
Deferred offering costs not yet paid		$ 686

Redeemable Convertible Preferred Shares

3 Months Ended

Mar. 31, 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 March 31, 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.

Defined Contribution Plan (Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Retirement Benefits [Abstract]
Matching Contribution	$ 200	$ 0

Equity-Based Compensation

3 Months Ended

Mar. 31, 2022

Stockholders' Equity Note [Abstract]

Equity-Based Compensation

Prior to the Conversion, Day One Holding LLC granted incentive shares under the Incentive Share Plan and was authorized to issue 8,924,177 incentive shares. Incentive shares were a separate non-voting 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:


		Three Months Ended March 31,
		2021
Common share fair value		$6.36 - $7.51
Participating threshold		$6.36
Risk free rate		0.14%
Volatility		72.90%
Time to liquidity (in years)		0.20 - 1.80
Grant date fair value		$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 three months ended March 31, 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

The following table provides a summary of the unvested common stock awards activity during the three months ended March 31, 2022.


	Number of Shares			Weighted Average Grant Date Fair Value
Unvested common stock as of December 31, 2021		3,753,862		$	16.00
Vested		(360,816	)	$	16.00
Forfeiture		(40,363	)	$	16.00
Unvested common stock as of March 31, 2022		3,352,683		$	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 three months ended March 31, 2022.


	Options			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2021		5,071,896		$	16.90
Granted		2,008,230		$	14.22
Forfeiture		(61,898	)	$	16.78
Outstanding at March 31, 2022		7,018,228		$	16.13		9.3	$	26
Exercisable at March 31, 2022		293,995		$	15.91		9.2	$	—

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 three months ended March 31, 2022 was $1.7 million. The weighted-average grant date fair value of options granted during the three months ended March 31, 2022 was $8.47 per share.

Unamortized stock-based compensation for stock options as of March 31, 2022 was $53.0 million, which is expected to be recognized over a weighted-average period of 3.3 years.

The following table provides a summary of restricted stock units activity under the 2021 Plan during the three months ended March 31, 2022:


	Number of Shares			Weighted Average Grant Date Fair Value
Unvested restricted stock units at December 31, 2021		96,890		$	22.93
Granted		311,945		$	14.21
Vested		(14,068	)	$	14.26
Forfeiture		(2,010	)	$	19.88
Unvested restricted stock units at March 31, 2022		392,757		$	16.33

Restricted stock units vest quarterly over four years with a one-year cliff from the grant date. Unamortized stock-based compensation for restricted stock units as of March 31, 2022 was $6.0 million, which is expected to be recognized over a weighted-average period of 3.7 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. 23,353 shares have been issued under the ESPP as of March 31, 2022. The Company recognized $0.1 million compensation expense related to the ESPP plan for the three months ending March 31, 2022.

Share/Stock-based compensation

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 March 31, 2022
	Stock Options
Expected term (in years)	5.90 - 6.08
Expected volatility	65.20% - 66.92%
Risk-free interest rate	1.47% - 2.55%
Expected dividend yield		—

For the three months ended March 31, 2022, the Company did not grant any ESPP awards.

Share/stock-based compensation expense recorded in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Loss is as follows (in thousands):


	Three Months Ended March 31,
	2022		2021
Research and development expense	$	2,147	$	119
General and administrative expense		4,055		419
Total share-based compensation expense	$	6,202	$	538

As of March 31, 2022, there was $70.9 million of unrecognized compensation cost related to unvested restricted stock, unvested restricted stock units and stock options that is expected to be recognized over a weighted-average period of approximately 3.1 years.

Balance Sheet Items

3 Months Ended

Mar. 31, 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):


	March 31, 2022		December 31, 2021
Prepaid insurance	$	874	$	2,099
Prepaid research and development expenses		3,365		1,945
Other prepaid expenses and other assets		398		1,015
Total prepaid expenses and other current assets	$	4,637	$	5,059

Property and Equipment, Net

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


	March 31, 2022			December 31, 2021
Furniture and fixtures	$	78		$	78
Leasehold improvements		14			15
Other property and equipment		15			—
Property and equipment, gross		107			93
Less: accumulated depreciation		(41	)		(36	)
Property and equipment, net	$	66		$	57

Depreciation expense for each of the three months ended March 31, 2022 and 2021 was immaterial.

Accrued Expenses and Other Current Liabilities

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


	March 31, 2022		December 31, 2021
Accrued payroll related expenses	$	1,648	$	3,308
Accrued research and development expenses		4,171		2,565
Accrued professional service expenses		1,098		732
Other		387		104
Total accrued expenses and other current liabilities	$	7,304	$	6,709

Redeemable NonControlling Interest - Additional Information (Detail) - USD ($) $ in Thousands		2 Months Ended	3 Months Ended		5 Months Ended
	May 26, 2021	May 26, 2021	Mar. 31, 2022	Mar. 31, 2021	May 26, 2021
Redeemable Noncontrolling Interest [Line Items]
Net loss attributable to redeemable convertible noncontrolling interests			$ 0	$ (919)
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
Net loss attributable to redeemable convertible noncontrolling interests				$ 900	$ 2,100

Equity-Based Compensation - Summary of The Black-Scholes Option Pricing Model to Estimate The Fair Value of Stock Option Granted (Detail) - Stock options	3 Months Ended
	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment award fair value assumptions dividend yield	0.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 29 days
Expected volatility	66.92%
Risk-free interest rate	2.55%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 10 months 24 days
Expected volatility	65.20%
Risk-free interest rate	1.47%

Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2022

Commitments and Contingencies Disclosure [Abstract]

Summary of Future Lease Obligations

As of March 31, 2022, the future lease obligations were as follows (in thousands):


For the Years Ending December 31,	March 31, 2022
Remaining in 2022	$	158
2023		18
Total future minimum lease payments		176
Less: Imputed interest		(5	)
Present value of operating lease liabilities	$	171

Defined Contribution Plan	3 Months Ended
Defined Contribution Plan	Mar. 31, 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 months ended March 31, 2022 and 2021, the Company made matching contributions of $0.2 million and zero, respectively.

Fair Value Measurement - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 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

Equity-Based Compensation - Summary of Fair Value of The Incentive Shares Estimated Using An Option Pricing Model (Detail) - Incentive Share Plan Member [Member]	3 Months Ended
	Mar. 31, 2021 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free rate	0.14%
Volatility	72.90%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common share fair value	$ 7.51
Time to liquidity (in years)	1 year 9 months 18 days
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	$ 4.52

Subsequent Event (Additional Information) (Details)	Apr. 01, 2022 USD ($) ft²
Subsequent Event [Line Items]
Total payments for base rent	$ 1,100,000
Subsequent Event
Subsequent Event [Line Items]
Sublease agreement area \| ft²	12,000
Initial lease term	31 months
Security deposit	$ 40,000
Lease commencement date	2022-05

Summary Of Significant Accounting Policies

3 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

There have been no changes to the significant accounting policies as disclosed in Note 2 to the Company’s annual consolidated financial statements for the years ended December 31, 2021 and 2020 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021.

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. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2022 are not necessarily indicative of the results that may be expected for the year ending December 31, 2022.

The condensed consolidated balance sheet at December 31, 2021, has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements.

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.

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 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.

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses:
Research and development	$ 15,003	$ 12,632
General and administrative	12,745	3,454
Total operating expenses	27,748	16,086
Loss from operations	(27,748)	(16,086)
Interest income (expense), net	2	(7)
Other expense	(1)	(8)
Net loss and comprehensive loss	(27,747)	(16,101)
Net loss attributable to redeemable convertible noncontrolling interests	0	(919)
Net loss attributable to common stockholders/members	$ (27,747)	$ (15,182)
Net loss per share, basic and diluted	$ (0.48)	$ (2.58)
Weighted-average number of common shares used in computing net loss per share, basic and diluted	58,382,444	5,892,145

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 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. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2022 are not necessarily indicative of the results that may be expected for the year ending December 31, 2022. The condensed consolidated balance sheet at December 31, 2021, has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. 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.
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 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.

Balance Sheet Items - Summary of Accrued expenses and other current liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued payroll related expenses	$ 1,648	$ 3,308
Accrued research and development expenses	4,171	2,565
Accrued professional service expenses	1,098	732
Other	387	104
Total accrued expenses and other current liabilities	$ 7,304	$ 6,709

Redeemable Convertible Preferred Shares - Additional Information (Detail) - USD ($)		1 Months Ended
	Jun. 01, 2021	Jun. 30, 2021	Feb. 28, 2021	Mar. 31, 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

Equity-Based Compensation - Summary of The Unvested Common Stock (Detail) - 2021 Stock Incentive Plan [Member]	3 Months Ended
	Mar. 31, 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	(360,816)
Forfeiture \| shares	(40,363)
Number of Shares, Unvasted Common Stock, Ending balance \| shares	3,352,683
Weighted Average Grant Date Fair Value, Beginning Balance	$ 16.00
Vested	16.00
Forfeiture	16.00
Weighted Average Grant Date Fair Value, Ending Balance	$ 16.00
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested \| shares	(14,068)
Weighted Average Grant Date Fair Value, Beginning Balance	$ 22.93
Vested	14.26
Forfeiture	19.88
Weighted Average Grant Date Fair Value, Ending Balance	$ 16.33

Common Stock - Additional Information (Detail)	1 Months Ended
Common Stock - Additional Information (Detail)	Nov. 30, 2018 USD ($) shares	Mar. 31, 2022 $ / shares shares	Dec. 31, 2021 $ / shares shares	Jun. 30, 2021 $ / shares shares
Class of Stock [Line Items]
Common Stock, Shares Authorized		500,000,000	500,000,000
Common Stock, Par or Stated Value Per Share \| $ / shares		$ 0.0001	$ 0.0001
Common Stock, Shares Issued		61,911,929	61,952,292
Common Stock, Shares Outstanding		61,911,929	61,952,292
Number of directors entitled to be elected by the holders of common stock	2
Common stock shares reserved for future issuance		10,692,078
Common Shares Purchase Agreement [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized				500,000,000
Common Stock, Par or Stated Value Per Share \| $ / shares				$ 0.0001
Common Stock, Shares Issued		61,911,929
Common Stock, Shares Outstanding		61,911,929
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

Description of Business and Organization

3 Months Ended

Mar. 31, 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 genomically-defined cancers. The Company’s lead product candidate, tovorafenib (DAY101), is an oral, brain-penetrant, highly-selective type II pan-RAF kinase inhibitor. 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 (collectively, “the Subsidiaries.”)

In December 2021, the Company’s board of directors approved the merger of the Subsidiaries with and into the Company, with the Company being the surviving corporation (collectively, the “Merger”), 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.

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] 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]
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 A redeemable convertible preferred shares, shares		9,638,141
Net loss attributable to redeemable convertible noncontrolling interests	(919)		$ (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, 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
Net loss attributable to redeemable convertible noncontrolling interests	0
Unvested stock forfeiture						(40,363)
Net loss attributable to common stockholders	(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

Commitment and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Lessee operating lease renewal lease term	9 months 18 days
Amortization of operating right-of-use assets	$ 47	$ 44
Research And Development Agreements
Lessee, Lease, Description [Line Items]
Termination and cancellation charges payable	0		$ 0
Viracta License Agreement
Lessee, Lease, Description [Line Items]
Royalty fee payable	0		0
Indemnification Agreement
Lessee, Lease, Description [Line Items]
Termination and cancellation charges payable	0		$ 0
Lease For Corporate Office Facility \| Central America
Lessee, Lease, Description [Line Items]
Tenant improvement allowances receivable	$ 10,000
Lessee operating lease incremental borrowing rate	8.00%
Lessee operating lease renewal lease term	3 years
Amortization of operating right-of-use assets	$ 47,000	44,000
Operating lease payments	$ 52,000	$ 51,000

Fair Value Measurement - Summary of Company's Financial Instruments (Detail) - Fair Value, Recurring [Member] - Money Market Funds [Member] - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash and cash equivalents	$ 90,265	$ 111,221
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	90,265	111,221
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, 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

Description of Business and Organization - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended
	Jun. 01, 2021	May 23, 2021	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from issuance of initial public offering	$ 167,000
Payments of stock issuance costs	$ 17,000
Share-based compensation arrangement by share-based payment award, options, vested, number of shares				4,719,605
Common stock shares authorized				500,000,000	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)				$ (155,234)	$ (127,487)
Cash and cash equivalents				$ 262,731	$ 284,309	$ 154,870	$ 43,728
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