0000950170-22-009937 | 10-Q | XBRL Viewer

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2022	Apr. 25, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Registrant Name	CULLINAN ONCOLOGY, INC.
Current Fiscal Year End Date	--12-31
Document Quarterly Report	true
Document Transition Report	false
Entity Central Index Key	0001789972
Entity File Number	001-39856
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3879991
Entity Address, Address Line One	One Main Street
Entity Address, Address Line Two	Suite 520
Entity Address, City or Town	Cambridge
Entity Address, Country	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	410-4650
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	CGEM
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		44,782,502

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 76,118	$ 59,774
Short-term investments	238,736	230,692
Prepaid expenses and other current assets	7,458	6,098
Total current assets	322,312	296,564
Property and equipment, net	64	77
Operating lease right-of-use assets	1,194	0
Other assets	147	147
Deferred tax assets	19,568
Long-term investments	94,178	140,397
Total assets	437,463	437,185
Current liabilities:
Accounts payable	6,306	3,169
Accrued expenses and other current liabilities	10,432	8,577
Operating lease liabilities, current	519	0
Total current liabilities	17,257	11,746
Long-term liabilities:
lease liabilities, non-current	736	0
Deferred rent	0	65
Total liabilities	17,993	11,811
Commitments and contingencies (Note 8)
Stockholders' equity:
Common stock, $0.0001 par value, 150,000,000 shares authorized as of March 31, 2022 and December 31, 2021; 44,660,026 and 44,292,102 shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively.	4	4
Additional paid-in capital	592,839	584,714
Accumulated other comprehensive loss	(3,134)	(838)
Accumulated deficit	(171,007)	(158,909)
Total Cullinan stockholders' equity	418,702	424,971
Noncontrolling interests	768	403
Total stockholders' equity	419,470	425,374
Total liabilities and stockholders' equity	$ 437,463	$ 437,185

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	44,660,026	44,292,102
Common stock, shares outstanding	44,660,026	44,292,102

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Revenue	$ 0	$ 18,943
Type of revenue [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember
Operating expenses:
Research and development	$ 24,536	$ 12,415
General and administrative	8,121	5,156
Total operating expenses	32,657	17,571
Income/(loss) from operations	(32,657)	1,372
Other income (expense):
Interest income	197	49
Other income (expense), net	0	(2)
Net income/(loss) before income taxes	(32,460)	1,419
Income tax expense/(benefit)	19,568	0
Net income/(loss)	(12,892)	1,419
Net income/(loss) attributable to noncontrolling interest	(794)	1,489
Net loss attributable to common stockholders of Cullinan	$ (12,098)	$ (70)
Net loss per share, basic and diluted	$ (0.27)	$ (0.00)
Total weighted-average shares used in computing net loss per share, basic and diluted	44,431,657	41,977,336
Comprehensive income/(loss):
Net income/(loss)	$ (12,892)	$ 1,419
Unrealized gain/(loss) on investments	(2,296)	(58)
Comprehensive income/(loss)	(15,188)	1,361
Comprehensive income/(loss) attributable to noncontrolling interest	(794)	1,489
Comprehensive income/(loss) attributable to Cullinan	$ (14,394)	$ (128)

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss)/Income	Accumulated Deficit	Noncontrolling Interest in Subsidiaries
Balances at Dec. 31, 2020	$ 200,314	$ 3	$ 292,348	$ (2)	$ (93,339)	$ 1,304
Balances, shares at Dec. 31, 2020		29,831,125
Initial public offering net of issuance costs of $22,870	264,516	$ 1	264,515
Initial public offering net of issuance costs of $22,870, shares		13,685,000
Equity-based compensation	3,508		3,503			5
Unrealized loss on investments	(58)			(58)
Net income/(loss)	1,419				(70)	1,489
Balances at Mar. 31, 2021	469,699	$ 4	560,366	(60)	(93,409)	2,798
Balances, shares at Mar. 31, 2021		43,516,125
Balances at Dec. 31, 2021	425,374	$ 4	584,714	(838)	(158,909)	403
Balances, shares at Dec. 31, 2021		44,292,102
Issuance of subsidiary preferred stock	1,153					1,153
Issuance of common stock upon vesting of RSUs		5,979
Equity-based compensation	6,565		6,559			6
Shares tendered for withholding taxes	(22)		(22)
Shares tendered for withholding taxes, Shares		(1,566)
Forfeiture of unvested restricted stock		(5,711)
Stock option exercises	1,588		1,588
Stock option exercises ,shares		369,222
Unrealized loss on investments	(2,296)			(2,296)
Net income/(loss)	(12,892)				(12,098)	(794)
Balances at Mar. 31, 2022	$ 419,470	$ 4	$ 592,839	$ (3,134)	$ (171,007)	$ 768
Balances, shares at Mar. 31, 2022		44,660,026

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Statement Of Stockholders Equity [Abstract]
Initial public offering, net of issuance costs	$ 22,870

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities:
Net income/(loss)	$ (12,892)	$ 1,419
Adjustments to reconcile net income/(loss) to net cash used in operating activities:
Depreciation and amortization	13	15
Equity-based compensation expense	6,565	3,508
Amortization or accretion on marketable securities	946	229
Deferred income tax benefit	(19,568)	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,140)	(4,352)
Accounts payable	3,137	(4,124)
Accrued expenses and other current liabilities	1,031	1,790
Net cash used in operating activities	(21,908)	(1,515)
Investing activities:
Purchase of marketable securities	(57,020)	(149,763)
Proceeds from sales and maturities of marketable securities	91,731	12,037
Net cash used in investing activities	34,711	(137,726)
Financing activities:
Proceeds from initial public offering	0	267,268
Payment of deferred offering costs	0	(2,688)
Proceeds from issuance of noncontrolling interests	1,153
Proceeds from issuance of convertible note	800
Proceeds from exercise of stock options	1,588
Net cash provided by financing activities	3,541	264,580
Net increase in cash and cash equivalents	16,344	125,339
Cash and cash equivalents at beginning of period	59,774	168,198
Cash and cash equivalents at end of period	76,118	293,537
Noncash financing activities
Deferred offering costs paid in the prior year	0	65
Tax withholding on stock awards not yet paid	$ 22

Nature of Business and Basis of Presentation

3 Months Ended

Mar. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of Business and Basis of Presentation

(1)

Nature of Business and Basis of Presentation

Organization

Cullinan Oncology, Inc., together with its consolidated subsidiaries (Cullinan or the Company), is a biopharmaceutical company developing a diversified pipeline of targeted oncology therapies for cancer patients. Cullinan’s predecessor company, Cullinan Pharmaceuticals, LLC was formed in September 2016 and was subsequently renamed Cullinan Oncology, LLC (the LLC) in November 2017. The LLC’s wholly-owned subsidiary, Cullinan Management, Inc. (Management), was formed in September 2016 and became the surviving entity in a reverse merger with the LLC in January 2021. In February 2021, the Company changed its name from Cullinan Management, Inc. to Cullinan Oncology, Inc.

As of March 31, 2022 and December 31, 2021, the Company had four development subsidiaries, or Asset Subsidiaries: Cullinan Amber Corp. (Amber), Cullinan Florentine Corp. (Florentine), Cullinan MICA Corp. (MICA) and Cullinan Pearl Corp. (Pearl).

Reorganization, Reverse Stock Split and Initial Public Offering

In January 2021, the Company completed its initial public offering (IPO) in which it issued and sold 13,685,000 shares of its common stock, including 1,785,000 shares sold pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a price to the public of $21.00 per share. The shares began trading on the Nasdaq Global Select Market on January 8, 2021 under the symbol “CGEM”. The net proceeds received by the Company from the offering were $264.5 million, after deducting underwriting discounts, commissions and other offering expenses.

Immediately prior to the effectiveness of the Company’s registration statement, the Company completed its reorganization, whereby the LLC merged with and into Management and Management was the surviving entity. Management was the registrant in the IPO.

Liquidity

The Company has incurred operating losses and negative cash flows from operations since its inception and expects to continue to generate operating losses for the foreseeable future. The Company’s ultimate success depends on the outcome of its research and development activities as well as the ability to commercialize the Company’s product candidates. The Company is subject to a number of risks including, but not limited to, the need to obtain adequate additional funding for the ongoing and planned clinical development of its product candidates. Due to the numerous risks and uncertainties associated with pharmaceutical products and development, the Company is unable to accurately predict the timing or amount of funds required to complete development of its product candidates, and costs could exceed the Company’s expectations for a number of reasons, including reasons beyond the Company’s control. The Company has incurred losses since inception and has an accumulated deficit of $171.0 million as of March 31, 2022.

Since inception, the Company has funded its operations primarily through the sale of equity securities. The Company expects that its cash, cash equivalents and short-term investments of $314.9 million and long-term investments and interest receivable of $95.4 million as of March 31, 2022, will be sufficient to fund its operating expenses and capital expenditure requirements through at least the next twelve months from the date of issuance of these unaudited consolidated financial statements. Interest receivable is included in prepaid expenses and other current assets on the consolidated balance sheet and represents accrued and unpaid interest on our marketable securities.

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

(2)

Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited consolidated financial statements of the Company have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP) and in accordance with applicable rules and regulations of the United States Securities and Exchange Commission (SEC) for interim financial reporting. The unaudited consolidated financial statements include accounts of the Company and its consolidated subsidiaries. All intercompany balances have been eliminated in consolidation. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASUs) of the Financial Accounting Standards Board (FASB).

The unaudited consolidated financial statements have been prepared on the same basis as the annual financial statements and in the opinion of the Company's management, reflect all adjustments, consisting of normal and recurring adjustments, considered necessary for a fair statement of the Company’s financial position, its results of operations and comprehensive income (loss) and its cash flows for the periods presented.

The unaudited consolidated financial statements herein do not include all of the disclosures required by GAAP for a complete set of annual audited financial statements, as is permitted by such rules and regulations. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company's Annual Report on Form 10-K filed with the SEC on March 17, 2022 for the year ended December 31, 2021 (the 2021 Form 10-K).

Use of Estimates

The preparation of the accompanying unaudited consolidated financial statements in accordance with GAAP requires the Company’s management to make estimates and judgments that may affect the reported amounts of assets, liabilities, revenues, expenses and related disclosure of contingent assets and liabilities. On an ongoing basis, the Company’s management evaluates the estimates, including those related to expenses and accruals. The Company’s management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Estimates and assumptions reflected in these unaudited consolidated financial statements include, but are not limited to, the fair value of the royalty transfer agreements, accrued research and development expenses, the fair value of equity awards issued by the Company and its subsidiaries prior to the IPO, income taxes and valuation allowance on deferred tax assets. Actual results may differ from these estimates under different assumptions or conditions.

Principles of Consolidation

The Company consolidates entities in which it has a controlling financial interest. The Company evaluates each of its subsidiaries to determine whether the entity represents a variable interest entity (VIE) for which consolidation should be evaluated under the VIE model, or alternatively, if the entity is a voting interest entity, for which consolidation should be evaluated using the voting interest model (VOE). The Company concluded that none of its subsidiaries is a VIE and has consolidated each subsidiary under the VOE. Under the VOE, the Company consolidates the entity if it determines 1) that it directly, or indirectly, has greater than 50% of the voting shares or other equity holders do not have substantive voting, participation, or liquidation rights, or 2) when the company has a controlling financial interest through its control of the board of directors, and the significant decisions of the entity are made at the board level.

The Company has either created or made investments in the following Asset Subsidiaries:


Consolidated Entities	Relationship as of March 31, 2022	Date Control First Acquired
Cullinan Amber Corp.	Partially-owned Subsidiary	December 2019
Cullinan Florentine Corp.	Partially-owned Subsidiary	December 2019
Cullinan Mica Corp.	Partially-owned Subsidiary	May 2020
Cullinan Pearl Corp.	Partially-owned Subsidiary	November 2018

Noncontrolling Interests

To the extent that ownership interests in the subsidiaries are held by entities other than the Company, management reports these as noncontrolling interests on the consolidated balance sheets. Earnings or losses are attributed to noncontrolling interests under the hypothetical liquidation at book value (HLBV) method. The HLBV method is a point in time calculation that utilizes inputs to determine the amount that the Company and the noncontrolling interest holders would receive upon a hypothetical liquidation at each balance sheet date based on the liquidation provisions of the respective articles of incorporation. At March 31, 2022, investors and licensors held noncontrolling interests in Amber, Florentine, MICA and Pearl. At March 31, 2021, investors and licensors held noncontrolling interests in Amber, Cullinan Apollo Corp. (Apollo), Florentine, MICA and Pearl. Apollo was dissolved in August 2021. Refer to Note 4 for details relating to the noncontrolling interests.

For the three months ended March 31, 2022 and 2021, $0.8 million of net loss and $1.5 million of net income, respectively, were attributable to noncontrolling interests and recorded in the consolidated statements of operations and comprehensive income (loss) and disclosed within the noncontrolling interests in subsidiaries column in the consolidated statements of stockholders’ equity.

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less at the time of purchase to be cash equivalents. As of March 31, 2022 and December 31, 2021, cash equivalents consist of government-backed money market funds.

Investments

Investments not classified as cash equivalents with maturities of less than twelve months are classified as short-term investments in the consolidated balance sheets. Investments with maturities greater than twelve months for which the Company has the intent and ability to hold the investment for greater than twelve months are classified as long-term investments in the consolidated balance sheets. The Company generally holds investments in marketable securities.

Marketable securities are carried at estimated fair value, with unrealized gains or losses included in accumulated other comprehensive income (loss) in stockholders’ equity. The fair value of marketable securities is based on available market information. The amortized cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization is included in interest income. Interest and dividends are also included in interest income. The Company periodically reviews its marketable securities for impairment and adjusts these investments to their fair value when a decline in market value is deemed to be other than temporary. Declines in fair value judged to be other-than-temporary on marketable securities, if any, are included in other income (expense), net.

The Company recognized its short-term and long-term investments by security type at March 31, 2022:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
Corporate notes	$	107,976	$	—	$	(842	)	$	107,134
Asset-backed securities		3,034		—		(36	)		2,998
Commercial paper		75,918		—		(189	)		75,729
US government notes		53,246		—		(371	)		52,875
Total short-term investments		240,174		—		(1,438	)		238,736
Long-term investments
Corporate notes		88,886		—		(1,584	)		87,302
Commercial paper		6,989		—		(113	)		6,876
Total long-term investments		95,875		—		(1,697	)		94,178
Total investments	$	336,049	$	—	$	(3,135	)	$	332,914

The Company recognized its short-term and long-term investments by security type at December 31, 2021:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
Corporate notes	$	98,642	$	—	$	(95	)	$	98,547
Commercial paper		114,174		—		(27	)		114,147
US government notes		18,033		—		(35	)		17,998
Total short-term investments		230,849		—		(157	)		230,692
Long-term investments
Corporate notes		117,868		—		(596	)		117,272
Asset-backed securities		3,044		—		(8	)		3,036
US government notes		20,166		—		(77	)		20,089
Total long-term investments		141,078		—		(681	)		140,397
Total investments	$	371,927	$	—	$	(838	)	$	371,089

Fair Value of Financial Instruments

The following table sets forth the fair value of the Company’s financial assets as of March 31, 2022, allocated into Level 1, Level 2 and Level 3, that was measured on a recurring basis:


	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash and cash equivalents
Cash	$	47,593	$	—	$	—	$	47,593
Money market funds		28,525		—		—		28,525
Total cash and cash equivalents		76,118		—		—		76,118
Short-term investments
Corporate notes		—		107,134		—		107,134
Asset-backed securities		—		2,998		—		2,998
Commercial paper		—		75,729		—		75,729
US government notes		—		52,875		—		52,875
Total short-term investments		—		238,736		—		238,736
Long-term investments
Corporate notes		—		87,302		—		87,302
US government notes		—		6,876		—		6,876
Total long-term investments		—		94,178		—		94,178
Total cash, cash equivalents and investments	$	76,118	$	332,914	$	—	$	409,032

The following table sets forth the fair value of the Company’s financial assets as of December 31, 2021, allocated into Level 1, Level 2 and Level 3, that was measured on a recurring basis:


	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash and cash equivalents
Cash	$	35,925	$	—	$	—	$	35,925
Money market funds		23,849		—		—		23,849
Total cash and cash equivalents		59,774		—		—		59,774
Short-term investments
Corporate notes		—		98,547		—		98,547
Commercial paper		—		114,147		—		114,147
US government notes		—		17,998		—		17,998
Total short-term investments		—		230,692		—		230,692
Long-term investments
Corporate notes		—		117,272		—		117,272
Asset-backed securities		—		3,036		—		3,036
US government notes		—		20,089		—		20,089
Total long-term investments		—		140,397		—		140,397
Total cash, cash equivalents and investments	$	59,774	$	371,089	$	—	$	430,863

Prepaid expenses and other current assets, accounts payable and accrued expenses and other current liabilities are carried at cost, which management believes approximates fair value due to their short-term nature.

Deferred Offering Costs

The Company capitalizes costs that are directly associated with in-process equity financings until such financings are consummated, at which time such costs are recorded against the gross proceeds of the offering. Should the in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations and comprehensive income (loss). The Company incurred $2.7 million of deferred offering costs in 2020 and recorded such amounts against the gross proceeds of the Company’s IPO within the statements of stockholders’ equity during the three months ended March 31, 2021.

Leases

On January 1, 2022, the Company adopted ASU 2016-02, Leases (Topic 842), or ASC 842, which requires lessees to recognize a lease liability and a right-of-use asset on the balance sheet for all leases, except certain short-term leases. In connection with its implementation of ASU 2016-02, the Company adopted the package of three practical expedients, allowing it to carry forward its previous lease classification and embedded lease evaluations and not to reassess initial direct costs as of the date of adoption. The Company also adopted the practical expedient where we combine lease and non-lease components for its real estate leases.

The Company’s existing lease obligations relating to a single, corporate location is subject to the new standard and resulted in recording of lease liabilities and right-of-use assets for operating leases on the Company’s balance sheet. The existing lease obligation is classified as an operating lease.

The below table details the balance sheet adjustments recorded on January 1, 2022 in connection with the Company’s adoption of ASU 2016-02 (in thousands):


		December 31, 2021							January 1, 2022
		As Reported under ASC 840			ASC 842 Adjustments				As Reported Under ASC 842
Assets
Operating lease right-of-use asset	$		—	$		1,311		$		1,311
Liabilities
Current portion of operating lease liabilities			—			505				505
Deferred rent			65			(65	)			—
Noncurrent portion of operating lease liabilities			—			871				871

In accordance with ASC 842, the Company determines if an arrangement is or contains a lease at inception. A contract is or contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. The Company classifies leases at the lease commencement date as operating or finance leases and records a right-of-use asset and a lease liability on the consolidated balance sheet for all leases with an initial lease term of greater than 12 months. Leases with an initial term of 12 months or less are not recorded in the balance sheet, but payments are recognized as expense on a straight-line basis over the lease term. The Company has elected not to recognize leases with terms of 12 months or less.

The Company enters into contracts that contain both lease and non-lease components. Non-lease components may include maintenance, utilities, and other operating costs. The Company combines the lease and non-lease components of fixed costs in its lease arrangements as a single lease component. Variable costs, such as utilities or maintenance costs, are not included in the measurement of right-of-use assets and lease liabilities, but rather are expensed when the event determining the amount of variable consideration to be paid occurs.

Operating lease assets and liabilities are recognized at the lease commencement date based on the present value of the lease payments over the lease term using the discount rate implicit in the lease. If the rate implicit is not readily determinable, the Company utilizes an estimate of its incremental borrowing rate based upon the available information at the lease commencement date. Operating lease assets are further adjusted for prepaid or accrued lease payments. Operating lease payments are expensed using the straight-line method as an operating expense over the lease term. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:


	March 31, 2022		December 31, 2021
	(in thousands)
Accrued bonus	$	799	$	2,576
Professional fees		1,438		973
Research and development expenses		7,391		5,028
Convertible note and accrued interest		804		—
	$	10,432	$	8,577

Revenue Recognition

The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers, or ASC 606. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

The Company enters into licensing arrangements for research and development, manufacturing and commercialization activities, which have components within the scope of ASC 606. Payments pursuant to these arrangements typically include non-refundable, upfront payments, milestone payments upon achieving significant development events, research and development reimbursements, sales milestones and royalties on future product sales. The amount of variable consideration is constrained until it is probable that the revenue is not at a significant risk of reversal in a future period. The contracts into which the Company enters generally do not include significant financing components. As part of the accounting for these arrangements, the Company must use significant judgment to determine: a) the number of performance obligations based on the determination under step (ii) above; b) the transaction price under step (iii) above; c) the stand-alone selling price for each performance obligation identified in the contract for the allocation of transaction price in step (iv) above, and d) the measure of progress in step (v) above. The Company uses judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described further below.

Non-Exclusive Licenses

If the license to the Company’s intellectual property is determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. In assessing whether a promise or performance obligation is distinct from the other elements, the Company considers factors such as the research, development, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the collaboration partner can benefit from a promise for its intended purpose without the receipt of the remaining elements, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise and whether it is separately identifiable from the remaining promise. For licenses that are combined with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The measure of progress, and thereby periods over which revenue should be recognized, are subject to estimates by management and may change over the course of the agreement. Such a change could have a material impact on the amount of revenue the Company records in future periods.

Milestone Payments

At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, clinical, regulatory, commercial and other risks that must be overcome to achieve the respective milestone in making this assessment. There is considerable judgment involved in determining whether it is probable that a significant revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment.

Royalties

For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license of intellectual property is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements.

Research and Development Expenses

Research and development costs are expensed as incurred and consist primarily of funds for employee wages and funds paid to third parties for the provision of services for product candidate development, clinical and preclinical development and related supply and manufacturing costs, and regulatory compliance costs. At the end of the reporting period, the Company compares payments made to third-party service providers to the estimated progress toward completion of the research or development objectives. Such estimates are subject to change as additional information becomes available. Depending on the timing of payments to the service providers and the progress that the Company estimates has been made as a result of the service provided, the Company may record net prepaid or accrued expense relating to these costs.

Costs incurred to obtain licenses are recognized as research and development expense as incurred if the technology licensed has no alternative future use. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are received or services are performed.

The Company has entered into various research and development related contracts with parties both inside and outside of the United States. The payments related to these agreements are recorded as research and development expenses as incurred. The Company records accrued liabilities for estimated ongoing research and development expenses. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. To date, there have been no material differences between the Company’s accrued costs and actual costs.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses in the consolidated statements of operations and comprehensive income (loss).

Equity-Based Compensation

Equity-based compensation is measured at the grant date for all equity-based awards made to employees and non-employees based on the fair value of the awards and is recognized as expense on a straight-line basis over the requisite service period, which is generally the vesting period. The Company has elected to recognize the actual forfeitures by reducing the equity-based compensation expense in the same period as the forfeitures occur.

The Company estimated the fair value of the stock options using the Black-Scholes option pricing model, which requires the input of objective and subjective assumptions. Certain assumptions used, including the fair value of the Company’s common stock prior to IPO and stock price volatility, represent management’s estimates and involve inherent uncertainties and the application of management’s judgment. As a result, if factors change and management uses different assumptions, equity-based compensation expense could be materially different for future awards.

The Company classifies equity-based compensation in its consolidated statements of operations and comprehensive income (loss) in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.

Income Taxes

The Company accounts for income taxes using the asset and liability method in accordance with FASB ASC Topic 740, Income Taxes. Current income taxes are based on taxable income for federal and state reporting purposes. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Deferred tax expense or benefit is the result of changes in deferred tax assets or liabilities. A valuation allowance is established to reduce deferred tax assets, when the Company concludes that it is more likely than not that some portion, or all of a deferred tax asset will not be realized. In evaluating its ability to recover deferred tax assets, the Company considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income.

The Company recognizes tax benefits from uncertain tax positions if we believe the position is more likely than not to be sustained on examination by the taxing authorities based on the technical merits of the position. The Company makes adjustments to these tax reserves when facts and circumstances change, such as the closing of a tax audit or the refinement of an estimate. The provision for income taxes includes the effects of any reserves for uncertain tax positions.

Net Loss per Share

Basic and diluted net loss per share is determined by dividing net loss attributable to common stockholders by the weighted-average shares of common stock outstanding during the period, without consideration for potential dilutive shares of common stock, such as stock options, unvested restricted stock awards and shares issuable under the employee stock purchase plan. Accordingly, in periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive shares of common stock are not assumed to have been issued if their effect is anti-dilutive. Therefore, the weighted-average shares used to calculate both basic and diluted net loss per share are the same for the periods presented. The Company excluded unvested shares of restricted stock awards, stock options and shares issuable under the employee stock purchase plan from the computation of diluted weighted-average shares outstanding as they would be antidilutive.

Recently Adopted Accounting Pronouncements

In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12), which is intended to simplify the accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The new standard became effective beginning January 1, 2022. The adoption of ASU 2019-12 did not have a material impact on the Company's consolidated financial position and consolidated results of operations.

License and Collaboration Agreements	3 Months Ended
License and Collaboration Agreements	Mar. 31, 2022
License And Collaboration Agreements [Abstract]
License and Collaboration Agreements	(3) License and Collaboration Agreements For the three months ended March 31, 2022, the Company recorded $0.5 million in research and development costs relating to the collaboration agreement with Adimab, LLC (Adimab) where the Company exercised its option to exploit Adimab's antibodies. For the three months ended March 31, 2021, the Company recorded $3.0 million within research and development costs relating to the license agreement with Taiho Pharmaceutical Co., Ltd (Taiho) through Cullinan Pearl.

Common Stock and Noncontrolling Interest in Subsidiaries

3 Months Ended

Mar. 31, 2022

Common Stock And Noncontrolling Interest In Subsidiaries [Abstract]

Common Stock and Noncontrolling Interest in Subsidiaries

(4)

Common Stock and Noncontrolling Interest in Subsidiaries

Common Stock

As of March 31, 2022 and December 31, 2021, 150,000,000 shares of common stock of the Company were authorized. Each share of common stock entitles the holder to one vote and to receive dividends when and if declared by the board of directors of the Company. No dividends have been declared through March 31, 2022.

Noncontrolling Interest in Subsidiaries

Certain subsidiaries issue common stock in connection with licensing agreements and to employees, directors and consultants pursuant to subsidiary equity incentive plans. The holders of subsidiary common stock are entitled to one vote per share. The holders of subsidiary common stock are entitled to receive dividends when and if declared by the subsidiaries’ board of directors and distributions in either case only after the payment of all preferential amounts required to be paid to the holders of shares of preferred stock of the respective subsidiary.

Cullinan Amber Corp.

In April 2020, in connection with its Series A Preferred Stock financing, Amber issued 3,000,000 shares of its Series A Preferred Stock to the Company for gross proceeds of $3.0 million. At any time following the initial closing, upon election of Amber’s board of directors, Amber may sell up to an aggregate of 9,000,000 shares of Amber’s Series A Preferred Stock at one or more subsequent closings at $1.00 per share.

In April 2020, pursuant to the license agreement (MIT License Agreement) between Amber and the Massachusetts Institute of Technology (MIT), Amber issued 400,132 shares of its common stock, in exchange for no additional consideration as set forth in the MIT License Agreement.

In June 2021, upon election by Amber’s board of directors, Amber issued an additional 3,000,000 shares of its Series A Preferred Stock to the Company for gross proceeds of $3.0 million. In connection with the financing, Amber issued 153,229 shares of its common stock to MIT in exchange for no additional consideration, as set forth in the MIT License Agreement.

The Company did not allocate any losses to the noncontrolling interests for each of the three months ended March 31, 2022 and 2021.

Cullinan Florentine Corp.

In August 2020, Florentine entered into a Series A Preferred Stock purchase agreement with the Company. The initial closing took place in August 2020 and Florentine sold 6,000,000 shares of its Series A Preferred Stock to the Company for gross proceeds of $6.0 million. At any time following the initial closing, upon the election of the Florentine’s board of directors, Florentine may sell up to an additional 6,000,000 shares of Series A Preferred Stock at one or more subsequent closings at $1.00 per share. Pursuant to the license agreement (Tübingen License Agreement) Florentine entered into with Deutsches Krebsforschungszentrum (DKFZ), Eberhard Karls University of Tübingen (University of Tübingen), and Universitätsmedizin Gesellschaft für Forschung und Entwicklung mbH, Tübingen (UFE), Florentine issued 725,118 shares of its common stock, in exchange for no additional consideration as set forth in the Tübingen License Agreement.

In December 2020, Florentine issued 6,000,000 additional shares of its Series A Preferred Stock to the Company for proceeds of $6.0 million under the Florentine Series A Preferred Stock purchase agreement. Florentine issued an additional 381,810 shares of its common stock to DKFZ and UFE as anti-dilution shares, in exchange for no additional consideration as set forth in the Tübingen License Agreement.

In July 2021, Florentine issued 7,500,000 shares of Series B Preferred Stock to the Company for gross proceeds of $8.1 million under the Florentine Series B Preferred Stock purchase agreement. No additional shares of its stock were issued to DKFZ or UFE.

The Company did not allocate any losses to the noncontrolling interests for each of the three months ended March 31, 2022 and 2021.

Cullinan MICA Corp.

In May 2020, MICA issued 6,088,282 million shares of Series A Senior Preferred Stock, including 5,385,787 shares to the Company, at $1.31 per share.

Using a market-based approach and an option-pricing allocation method, MICA determined the fair market value of MICA’s equity at acquisition was $12.8 million, of which $7.1 million was allocated to the Company’s Series A Senior Preferred Stock position, and $5.7 million was initially allocated to noncontrolling interests, including the Junior Preferred and Common Stockholders.

In December 2020, the MICA board authorized the issuance of 3,367,804 shares of MICA common stock to the Company, at a purchase price of $0.23 per share for aggregate proceeds to MICA of $0.8 million.

In June 2021, the MICA board authorized the First Additional Closing of the Series A Senior Preferred Stock financing and the Company purchased an additional 5,385,787 shares of Series A Senior Preferred Stock for $7.1 million and certain existing shareholders purchased an additional 702,495 shares of Series A Senior Preferred Stock for $0.9 million. Following the First Additional Closing, the Company’s ownership increased to 45% of MICA’s fully-diluted shares outstanding.

In March 2022, Cullinan MICA’s board of directors authorized the Second Additional Closing of the Series A Senior Preferred Stock financing where investors of Series A Senior Preferred Stock purchased another $10.0 million of Series A Senior Preferred Stock of Cullinan MICA. The Company purchased 6,732,232 shares while other existing investors purchased 878,118 shares for $8.8 million and $1.2 million, respectively. As a result of these transactions, the Company's ownership percentage in Cullinan MICA increased to 54%, which remains as of March 31, 2022.

Under the HLBV method, $0.5 million and $0.2 million of losses were attributed to noncontrolling interests for the three months ended March 31, 2022 and 2021, respectively.

Cullinan Pearl Corp.

In February 2019, Pearl entered into a Series A Preferred Stock Purchase Agreement with Taiho Ventures, LLC, an affiliate of Taiho, (Taiho Ventures) to sell up to 23,000,000 shares of Pearl’s Series A Preferred Stock for $1.00 per share. Pearl completed the initial closing of its Series A Preferred Stock where Pearl issued 14,000,000 shares of Series A Preferred Stock for $14.0 million to the Company and Taiho Ventures. In connection with the licensing agreement we entered into with Taiho in February 2019 (the Taiho License Agreement), Pearl issued 1,860,000 shares of its common stock to Taiho Ventures as anti-dilution shares, in exchange for no cash consideration.

In August 2020, Pearl issued 9,000,000 additional shares of its Series A Preferred Stock for $9.0 million to the Company and Taiho Ventures. In connection with the Taiho License Agreement, Pearl then issued 1,206,000 to Taiho Ventures additional shares of its common stock as anti-dilution shares, in exchange for no additional consideration.

In November 2020, pursuant to a subscription agreement between the Company and Pearl, the Company purchased 2,730,227 shares of Pearl’s common stock at $0.44 per share, for an aggregate purchase price of $1.2 million.

In March 2022, Pearl entered into a Note Purchase Agreement, or the Note, with the Company and Taiho Ventures pursuant to which Pearl agreed to issue up to $6.0 million in convertible promissory notes that is convertible into the next series of preferred stock. In March 2022, the first closing of the Note took place in which Pearl issued $3.2 million and $0.8 million to the Company and Taiho Ventures, respectively.

Under the HLBV method, $0.3 million of losses and $1.7 million of income were attributed to noncontrolling interests for the three months ended March 31, 2022 and 2021, respectively.

Equity-Based Compensation

3 Months Ended

Mar. 31, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Equity-Based Compensation

(5)

Equity-Based Compensation

The Company recorded equity-based compensation in the following expense categories in the consolidated statements of operations and comprehensive income (loss):


	Three Months Ended March 31,
	2022		2021
	(in thousands)
Research and development	$	2,660	$	1,569
General and administrative		3,905		1,939
Total equity-based compensation	$	6,565	$	3,508

Related Party Transactions

3 Months Ended

Mar. 31, 2022

Related Party Transactions

(6)

Related Party Transactions

In April 2020, the Company entered into a consulting agreement (the Globeways Agreement) with Globeways Holdings Limited, or Globeways. Globeways and entities affiliated with F2 Ventures beneficially own in the aggregate greater than five percent of the Company’s outstanding shares and Globeways is beneficially owned by a member of the Company’s board of directors. Pursuant to the Globeways Agreement, the board member provides leadership and advice regarding the Company’s scientific, clinical, product development and related activities and operations. Pursuant to the Globeways Agreement, the Company pays Globeways a consulting fee at a monthly rate of $25,000. As the sole beneficial owner of Globeways, this board member receives all of the compensation paid to Globeways under the Globeways Agreement.

The Company did not incur any expenses relating to the Globeways Agreement for the three months ended March 31, 2022 as the agreement expired as of March 31, 2021. For the three months ended March 31, 2021, the Company incurred less than $0.1 million in costs related to the Globeways Agreement.

Royalty Transfer Agreements

Between October 2019 and May 2020, each of the Asset Subsidiaries entered into royalty transfer agreements with MPM Oncology Charitable Foundation, Inc. and UBS Optimus Foundation (together, the Foundations). Under each of these respective agreements, each Foundation is entitled to receive a royalty equal to 0.5% (1.0% in aggregate) of all global net sales of any products developed by the applicable subsidiary, subject to limitations after patent expirations and on intellectual property developed after a change of control. The Company has deemed these royalty transfer agreements to be freestanding financial instruments that should be accounted for at fair value. Management of the Company has concluded that these instruments had no value at the inception of the agreements and at March 31, 2022 and December 31, 2021.

Given the early-stage nature of the underlying technologies and inherent technical, regulatory and competitive risks associated with achieving approval and commercialization, the Company ascribed no value to the royalty transfer agreements as of March 31, 2022 and December 31, 2021. The Company currently does not have any applicable net sales from its products and as a result, has paid no royalties under these obligation as of March 31, 2022 and December 31, 2021 nor has the Company accrued any liability as of such dates. The Company will monitor these instruments for changes in fair value at each reporting date.

Income Taxes

3 Months Ended

Mar. 31, 2022

Income Tax Disclosure [Abstract]

Income Taxes

(7)

Income Taxes

For the three months ended March 31, 2022, the Company recorded an income tax benefit of $19.6 million. The tax benefit recorded for the three months ended March 31, 2022 was driven by the expected utilization of the current quarter's net operating losses based on the effective tax rate and the release of valuation allowance for certain historical tax losses against the expected gain from the sale of Cullinan Pearl. Refer to Note 12, Subsequent Events, for additional details on this transaction. The Company did not record an income tax benefit or expense for the three months ended March 31, 2021.

Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax bases of assets and liabilities using statutory rates. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating loss carryforwards and research and development credits. The Company has considered its history of cumulative net losses, estimated future taxable income and prudent and feasible tax planning strategies. The Company has concluded that it is more likely than not that the Company will not realize the benefits of its deferred tax assets outside of the tax losses that will be utilized against the expected gain from the sale of Cullinan Pearl. As a result, as of March 31, 2022, the Company has maintained a full valuation allowance against its remaining net deferred tax assets.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: 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(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Commitments and Contingencies

3 Months Ended

Mar. 31, 2022

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

(8)

Commitment and Contingencies

The Company enters into contracts in the normal course of business with contract research organizations, or CROs, contract manufacturing organizations, or CMOs, and other third parties for preclinical research studies, clinical trials and testing and manufacturing services. These contracts do not contain minimum purchase commitments and are cancelable upon prior written notice. Payments due upon cancellation consist only of payments for services provided or expenses incurred, including noncancelable obligations of service providers, up to the date of cancellation.

Indemnification agreements

In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessor, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in certain cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not aware of any indemnification arrangements that could have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of March 31, 2022 and December 31, 2021.

Legal proceedings

The Company is not currently party to and is not aware of any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings.

Leases

3 Months Ended

Mar. 31, 2022

Leases [Abstract]

Leases

(9)

Leases

In December 2017, the Company signed an operating lease for 7,531 rentable square feet of office space in Cambridge, Massachusetts, which commenced on February 1, 2018. The lease expires on June 30, 2024. Rent expense is recorded ratably over the lease period. The lease includes escalating rental payments, which are also being charged to rent expense ratably over the lease period.

The components of lease expense are as follows (in thousands):


		Three Months Ended March 31, 2022
Operating lease costs	$	147
Short term lease costs		—
Variable lease costs		—

The following table summarizes supplemental cash flow information (in thousands):


		Three Months Ended March 31, 2022
Cash paid for amounts included in measurement of lease liabilities:
Operating cash flows from operating leases	$	151
ROU asset obtained in exchange for an operating lease liability		1,311

The following table summarizes the Company’s future minimum lease payments and reconciliation of lease liabilities (in thousands):


		As of March 31, 2022
Remainder of 2022		$457
2023		618
2024		313
Total future minimum lease payments		$1,388
Less: imputed interest		(133)
Total lease liabilities at present value		$1,255
Lease liabilities, current		$519
Lease liabilities, non-current		$736

The following table summarizes lease term and discount rate:


	Three Months Ended March 31, 2022
Weighted-average remaining lease term (years)	2.3
Weighted-average discount rate	9.5%

As the Company’s operating leases did not provide an implicit rate, the Company used its incremental borrowing rate based on the information available in determining the present value of lease payments. The Company’s incremental borrowing rate was based on the term of the lease, the economic environment of the lease and reflect the rate the Company would have had to pay to borrow on a secured basis.

Employee Benefit Plan	3 Months Ended
Employee Benefit Plan	Mar. 31, 2022
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	(10) Employee Benefit Plan The Company maintains a defined contribution 401(k) plan (the 401(k) Plan) in which employees may contribute a portion of their compensation, subject to statutory maximum contribution amounts. The Company assumes all administrative costs of the 401(k) Plan. For the each of three months ended March 31, 2022 and 2021, the expense relating to the matching contribution was $0.1 million and less than $0.1 million, respectively.

Net Loss per Share

3 Months Ended

Mar. 31, 2022

Earnings Per Share [Abstract]

Net Loss per Share

(11)

Net Loss per Share

The following table sets forth the calculation of basic and diluted net loss per share:


	Three Months Ended March 31,
	2022			2021
	(in thousands, except share and per share data)
Numerator:
Net loss attributable to common stockholders of Cullinan	$	(12,098	)	$	(70	)
Denominator
Total weighted-average shares used in computing net loss per share, basic and diluted		44,431,657			41,977,336
Net loss per share:	$	(0.27	)	$	(0.00	)

The following table sets forth equity instruments that were excluded from the computation of the diluted net loss per share for the periods presented because their effect would have been anti-dilutive:


	As of March 31,
	2022		2021
Restricted stock awards		73,448		242,411
Stock options		9,985,444		6,600,953
Estimated shares issuable under the ESPP		6,922		10,101
Total		10,065,814		6,853,465

Subsequent Events

3 Months Ended

Mar. 31, 2022

Subsequent Events [Abstract]

Subsequent Events

(12) Subsequent Events

In May 2022, the Company announced an agreement pursuant to which Taiho will acquire Cullinan Pearl and Taiho Oncology, Inc., an affiliate of Taiho, will concurrently enter into a U.S. co-development and co-commercialization agreement for CLN-081 with the Company. Upon closing of the transaction, the Company will receive an upfront payment of $275.0 million, subject to customary closing conditions, including the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended. The Company will also be eligible to receive an additional $130.0 million tied to EGFR exon20 non-small cell lung cancer (NSCLC) regulatory milestones. In accordance with the co-development and co-commercialization agreement, the Company will share 50% of the development costs and also 50% of the future potential pre-tax net profit in the U.S. for CLN-081.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Basis of Presentation

Use of Estimates

Principles of Consolidation

The Company has either created or made investments in the following Asset Subsidiaries:


Consolidated Entities	Relationship as of March 31, 2022	Date Control First Acquired
Cullinan Amber Corp.	Partially-owned Subsidiary	December 2019
Cullinan Florentine Corp.	Partially-owned Subsidiary	December 2019
Cullinan Mica Corp.	Partially-owned Subsidiary	May 2020
Cullinan Pearl Corp.	Partially-owned Subsidiary	November 2018

Noncontrolling Interests

Cash and Cash Equivalents

Investments

The Company recognized its short-term and long-term investments by security type at March 31, 2022:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
Corporate notes	$	107,976	$	—	$	(842	)	$	107,134
Asset-backed securities		3,034		—		(36	)		2,998
Commercial paper		75,918		—		(189	)		75,729
US government notes		53,246		—		(371	)		52,875
Total short-term investments		240,174		—		(1,438	)		238,736
Long-term investments
Corporate notes		88,886		—		(1,584	)		87,302
Commercial paper		6,989		—		(113	)		6,876
Total long-term investments		95,875		—		(1,697	)		94,178
Total investments	$	336,049	$	—	$	(3,135	)	$	332,914

The Company recognized its short-term and long-term investments by security type at December 31, 2021:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
Corporate notes	$	98,642	$	—	$	(95	)	$	98,547
Commercial paper		114,174		—		(27	)		114,147
US government notes		18,033		—		(35	)		17,998
Total short-term investments		230,849		—		(157	)		230,692
Long-term investments
Corporate notes		117,868		—		(596	)		117,272
Asset-backed securities		3,044		—		(8	)		3,036
US government notes		20,166		—		(77	)		20,089
Total long-term investments		141,078		—		(681	)		140,397
Total investments	$	371,927	$	—	$	(838	)	$	371,089

Fair Value of Financial Instruments

The following table sets forth the fair value of the Company’s financial assets as of March 31, 2022, allocated into Level 1, Level 2 and Level 3, that was measured on a recurring basis:


	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash and cash equivalents
Cash	$	47,593	$	—	$	—	$	47,593
Money market funds		28,525		—		—		28,525
Total cash and cash equivalents		76,118		—		—		76,118
Short-term investments
Corporate notes		—		107,134		—		107,134
Asset-backed securities		—		2,998		—		2,998
Commercial paper		—		75,729		—		75,729
US government notes		—		52,875		—		52,875
Total short-term investments		—		238,736		—		238,736
Long-term investments
Corporate notes		—		87,302		—		87,302
US government notes		—		6,876		—		6,876
Total long-term investments		—		94,178		—		94,178
Total cash, cash equivalents and investments	$	76,118	$	332,914	$	—	$	409,032

The following table sets forth the fair value of the Company’s financial assets as of December 31, 2021, allocated into Level 1, Level 2 and Level 3, that was measured on a recurring basis:


	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash and cash equivalents
Cash	$	35,925	$	—	$	—	$	35,925
Money market funds		23,849		—		—		23,849
Total cash and cash equivalents		59,774		—		—		59,774
Short-term investments
Corporate notes		—		98,547		—		98,547
Commercial paper		—		114,147		—		114,147
US government notes		—		17,998		—		17,998
Total short-term investments		—		230,692		—		230,692
Long-term investments
Corporate notes		—		117,272		—		117,272
Asset-backed securities		—		3,036		—		3,036
US government notes		—		20,089		—		20,089
Total long-term investments		—		140,397		—		140,397
Total cash, cash equivalents and investments	$	59,774	$	371,089	$	—	$	430,863

Deferred Offering Costs

Leases

The below table details the balance sheet adjustments recorded on January 1, 2022 in connection with the Company’s adoption of ASU 2016-02 (in thousands):


		December 31, 2021							January 1, 2022
		As Reported under ASC 840			ASC 842 Adjustments				As Reported Under ASC 842
Assets
Operating lease right-of-use asset	$		—	$		1,311		$		1,311
Liabilities
Current portion of operating lease liabilities			—			505				505
Deferred rent			65			(65	)			—
Noncurrent portion of operating lease liabilities			—			871				871

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:


	March 31, 2022		December 31, 2021
	(in thousands)
Accrued bonus	$	799	$	2,576
Professional fees		1,438		973
Research and development expenses		7,391		5,028
Convertible note and accrued interest		804		—
	$	10,432	$	8,577

Revenue Recognition

Non-Exclusive Licenses

Milestone Payments

Royalties

Research and Development Expenses

Patent Costs

Equity-based Compensation

Equity-Based Compensation

Income Taxes

Net Loss per Share

Recently Adopted Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Schedule of Short-term and Long-term Investment Marketable Securities by Security Type

The Company recognized its short-term and long-term investments by security type at March 31, 2022:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
Corporate notes	$	107,976	$	—	$	(842	)	$	107,134
Asset-backed securities		3,034		—		(36	)		2,998
Commercial paper		75,918		—		(189	)		75,729
US government notes		53,246		—		(371	)		52,875
Total short-term investments		240,174		—		(1,438	)		238,736
Long-term investments
Corporate notes		88,886		—		(1,584	)		87,302
Commercial paper		6,989		—		(113	)		6,876
Total long-term investments		95,875		—		(1,697	)		94,178
Total investments	$	336,049	$	—	$	(3,135	)	$	332,914

The Company recognized its short-term and long-term investments by security type at December 31, 2021:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term investments
Corporate notes	$	98,642	$	—	$	(95	)	$	98,547
Commercial paper		114,174		—		(27	)		114,147
US government notes		18,033		—		(35	)		17,998
Total short-term investments		230,849		—		(157	)		230,692
Long-term investments
Corporate notes		117,868		—		(596	)		117,272
Asset-backed securities		3,044		—		(8	)		3,036
US government notes		20,166		—		(77	)		20,089
Total long-term investments		141,078		—		(681	)		140,397
Total investments	$	371,927	$	—	$	(838	)	$	371,089

Summary of Fair Value of Financial Assets Measured on Recurring Basis

The following table sets forth the fair value of the Company’s financial assets as of March 31, 2022, allocated into Level 1, Level 2 and Level 3, that was measured on a recurring basis:


	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash and cash equivalents
Cash	$	47,593	$	—	$	—	$	47,593
Money market funds		28,525		—		—		28,525
Total cash and cash equivalents		76,118		—		—		76,118
Short-term investments
Corporate notes		—		107,134		—		107,134
Asset-backed securities		—		2,998		—		2,998
Commercial paper		—		75,729		—		75,729
US government notes		—		52,875		—		52,875
Total short-term investments		—		238,736		—		238,736
Long-term investments
Corporate notes		—		87,302		—		87,302
US government notes		—		6,876		—		6,876
Total long-term investments		—		94,178		—		94,178
Total cash, cash equivalents and investments	$	76,118	$	332,914	$	—	$	409,032

The following table sets forth the fair value of the Company’s financial assets as of December 31, 2021, allocated into Level 1, Level 2 and Level 3, that was measured on a recurring basis:


	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash and cash equivalents
Cash	$	35,925	$	—	$	—	$	35,925
Money market funds		23,849		—		—		23,849
Total cash and cash equivalents		59,774		—		—		59,774
Short-term investments
Corporate notes		—		98,547		—		98,547
Commercial paper		—		114,147		—		114,147
US government notes		—		17,998		—		17,998
Total short-term investments		—		230,692		—		230,692
Long-term investments
Corporate notes		—		117,272		—		117,272
Asset-backed securities		—		3,036		—		3,036
US government notes		—		20,089		—		20,089
Total long-term investments		—		140,397		—		140,397
Total cash, cash equivalents and investments	$	59,774	$	371,089	$	—	$	430,863

Supplemental Balance Sheet Information Related to Operating Leases

The below table details the balance sheet adjustments recorded on January 1, 2022 in connection with the Company’s adoption of ASU 2016-02 (in thousands):


		December 31, 2021							January 1, 2022
		As Reported under ASC 840			ASC 842 Adjustments				As Reported Under ASC 842
Assets
Operating lease right-of-use asset	$		—	$		1,311		$		1,311
Liabilities
Current portion of operating lease liabilities			—			505				505
Deferred rent			65			(65	)			—
Noncurrent portion of operating lease liabilities			—			871				871

Summary of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:


	March 31, 2022		December 31, 2021
	(in thousands)
Accrued bonus	$	799	$	2,576
Professional fees		1,438		973
Research and development expenses		7,391		5,028
Convertible note and accrued interest		804		—
	$	10,432	$	8,577

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Accrued Expenses and Other Current Liabilities (Tables)

3 Months Ended

Mar. 31, 2022

Accrued Expenses And Other Current Liabilities [Abstract]

Summary of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:


	March 31, 2022		December 31, 2021
	(in thousands)
Accrued bonus	$	799	$	2,576
Professional fees		1,438		973
Research and development expenses		7,391		5,028
Convertible note and accrued interest		804		—
	$	10,432	$	8,577

Equity-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Equity-based Compensation Expense Categories In Consolidated Statements of Operations and Comprehensive Income (Loss)

The Company recorded equity-based compensation in the following expense categories in the consolidated statements of operations and comprehensive income (loss):


	Three Months Ended March 31,
	2022		2021
	(in thousands)
Research and development	$	2,660	$	1,569
General and administrative		3,905		1,939
Total equity-based compensation	$	6,565	$	3,508

Leases (Tables)

3 Months Ended

Mar. 31, 2022

Leases [Abstract]

Components of Lease Costs

The components of lease expense are as follows (in thousands):


		Three Months Ended March 31, 2022
Operating lease costs	$	147
Short term lease costs		—
Variable lease costs		—

Supplemental Cash Flow Information Relating to Leases

The following table summarizes supplemental cash flow information (in thousands):


		Three Months Ended March 31, 2022
Cash paid for amounts included in measurement of lease liabilities:
Operating cash flows from operating leases	$	151
ROU asset obtained in exchange for an operating lease liability		1,311

Summarizes of future minimum lease payments

The following table summarizes the Company’s future minimum lease payments and reconciliation of lease liabilities (in thousands):


		As of March 31, 2022
Remainder of 2022		$457
2023		618
2024		313
Total future minimum lease payments		$1,388
Less: imputed interest		(133)
Total lease liabilities at present value		$1,255
Lease liabilities, current		$519
Lease liabilities, non-current		$736

Summarizes Lease Term and Discount Rate

The following table summarizes lease term and discount rate:


	Three Months Ended March 31, 2022
Weighted-average remaining lease term (years)	2.3
Weighted-average discount rate	9.5%

Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2022

Commitments And Contingencies Disclosure [Abstract]

Summary of Future Minimum Payments Due Under Operating Lease

The following table summarizes the Company’s future minimum lease payments and reconciliation of lease liabilities (in thousands):


		As of March 31, 2022
Remainder of 2022		$457
2023		618
2024		313
Total future minimum lease payments		$1,388
Less: imputed interest		(133)
Total lease liabilities at present value		$1,255
Lease liabilities, current		$519
Lease liabilities, non-current		$736

Net Loss per Share (Tables)

3 Months Ended

Mar. 31, 2022

Earnings Per Share [Abstract]

Summary of Calculation of Basic and Diluted Net Loss Per Share

The following table sets forth the calculation of basic and diluted net loss per share:


	Three Months Ended March 31,
	2022			2021
	(in thousands, except share and per share data)
Numerator:
Net loss attributable to common stockholders of Cullinan	$	(12,098	)	$	(70	)
Denominator
Total weighted-average shares used in computing net loss per share, basic and diluted		44,431,657			41,977,336
Net loss per share:	$	(0.27	)	$	(0.00	)

Summary of Outstanding Equity Instruments Excluded from Computation of Diluted Net Loss Per Share


	As of March 31,
	2022		2021
Restricted stock awards		73,448		242,411
Stock options		9,985,444		6,600,953
Estimated shares issuable under the ESPP		6,922		10,101
Total		10,065,814		6,853,465

Nature of Business and Basis of Presentation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Nature Of Business And Basis Of Presentation [Line Items]
Proceeds from initial public offering	$ 264,500	$ 0	$ 267,268
Long-term investments and interest receivables		95,400
Accumulated deficit		(171,007)		$ (158,909)
Cash, cash equivalents, short-term investments and long-term investments		$ 314,900
IPO
Nature Of Business And Basis Of Presentation [Line Items]
Common stock shares issued and sold	13,685,000
Stock, price per Share	$ 21.00
Underwriters' Option
Nature Of Business And Basis Of Presentation [Line Items]
Common stock shares issued and sold	1,785,000

- Definition

The cumulative amount of the reporting entity's undistributed earnings or deficit.

+ References + Details

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accounting Policies [Abstract]
Net loss attributable to noncontrolling interests	$ (0.8)	$ 1.5
Deferred offering costs	$ 2.7
Operating Lease Term	12 months

Summary of Significant Accounting Policies - Schedule of Short-term and Long-term Investment Marketable Securities by Security Type (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	$ 336,049	$ 371,927
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3,135)	(838)
Estimated Fair Value	332,914	371,089
Long Term Investment
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	95,875	141,078
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1,697)	(681)
Estimated Fair Value	94,178	140,397
Long Term Investment \| US Government Notes
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost		20,166
Gross Unrealized Gains		0
Gross Unrealized Losses		(77)
Estimated Fair Value		20,089
Corporate Note Securities \| Long Term Investment
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	88,886	117,868
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1,584)	(596)
Estimated Fair Value	87,302	117,272
Asset-backed Securities \| Long Term Investment
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost		3,044
Gross Unrealized Gains		0
Gross Unrealized Losses		(8)
Estimated Fair Value		3,036
Commercial Paper \| Long Term Investment
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	6,989
Gross Unrealized Gains	0
Gross Unrealized Losses	(113)
Estimated Fair Value	6,876
Short Term Investments
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	240,174	230,849
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1,438)	(157)
Estimated Fair Value	238,736	230,692
Short Term Investments \| US Government Notes
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	53,246	18,033
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(371)	(35)
Estimated Fair Value	52,875	17,998
Short Term Investments \| Corporate Note Securities
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	107,976	98,642
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(842)	(95)
Estimated Fair Value	107,134	98,547
Short Term Investments \| Asset-backed Securities
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	3,034
Gross Unrealized Gains	0
Gross Unrealized Losses	(36)
Estimated Fair Value	2,998
Short Term Investments \| Commercial Paper
Available For Sale Securities Fair Value To Amortized Cost Basis [Line Items]
Amortized Cost	75,918	114,174
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(189)	(27)
Estimated Fair Value	$ 75,729	$ 114,147

Summary of Significant Accounting Policies - Summary of Fair Value of Financial Assets Measured on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	$ 76,118	$ 59,774
Total short-term investments	238,736	230,692
Total long-term investments	94,178	140,397
Assets Fair Value Disclosure, Total	409,032	430,863
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	76,118	59,774
Assets Fair Value Disclosure, Total	76,118	59,774
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	238,736	230,692
Total long-term investments	94,178	140,397
Assets Fair Value Disclosure, Total	332,914	371,089
US Government Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	52,875	17,998
Total long-term investments	6,876	20,089
US Government Notes \| Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	52,875	17,998
Total long-term investments	6,876	20,089
Cash
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	47,593	35,925
Cash \| Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	47,593	35,925
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	28,525	23,849
Money Market Funds \| Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	28,525	23,849
Corporate Note Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	107,134	98,547
Total long-term investments	87,302	117,272
Corporate Note Securities \| Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	107,134	98,547
Total long-term investments	87,302	117,272
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	75,729	114,147
Commercial Paper \| Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	75,729	114,147
Asset-backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	2,998
Total long-term investments		3,036
Asset-backed Securities \| Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 2,998
Total long-term investments		$ 3,036

Summary of Significant Accounting Policies - Supplemental Balance Sheet Information Related to Operating Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Jan. 01, 2022	Dec. 31, 2021
Operating lease right-of-use assets	$ 1,194		$ 0
Operating lease liabilities, current	519		0
Deferred rent	0		65
Noncurrent portion of operating lease liabilities	736		0
As Reported
Operating lease right-of-use assets		$ 1,311	0
Operating lease liabilities, current		505	0
Deferred rent		0	65
Noncurrent portion of operating lease liabilities		$ 871	$ 0
Adjustment
Operating lease right-of-use assets	1,311
Operating lease liabilities, current	505
Deferred rent	(65)
Noncurrent portion of operating lease liabilities	$ 871

Summary of Significant Accounting Policies - Summary of Accrued expenses and other current labilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued bonus	$ 799	$ 2,576
Professional fees	1,438	973
Research and development expenses	7,391	5,028
Accrued Convertible Note and Accrued Interest	804	0
Accrued expenses and other current liabilities	$ 10,432	$ 8,577

Reorganization and Reverse Stock Split - Summary of LLC Units Previously Reported as Redeemable Preferred Units or Temporary Equity Converted Reclassified to Equity (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Stockholders' Equity (Members' Deficit)
Common Stock	$ 4	$ 4
Additional paid-in capital	592,839	584,714
Accumulated other comprehensive loss	(3,134)	(838)
Accumulated deficit	(171,007)	(158,909)
Total Cullinan Stockholders' Equity (Members' Deficit)	418,702	424,971
Non-controlling interests in subsidiaries	768	403
Total Stockholders' Equity (Members' Deficit)	$ 419,470	$ 425,374	$ 469,699	$ 200,314

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References + Details

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).

+ References

Reference 1: 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 http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(24))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123596393&loc=d3e14064-108612

Reference 4: 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 http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
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+ Details

- Definition

The cumulative amount of the reporting entity's undistributed earnings or deficit.

+ References + Details

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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+ Details

- Definition

Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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+ Details

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued bonus	$ 799	$ 2,576
Professional fees	1,438	973
Research and development expenses	7,391	5,028
Accrued expenses and other current liabilities	$ 10,432	$ 8,577

License and Collaboration Agreements - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
License And Collaboration Agreements [Line Items]
Research and development costs	$ 24,536	$ 12,415
Collaboration and License Agreements
License And Collaboration Agreements [Line Items]
Research and development costs		$ 3,000
Adimab
License And Collaboration Agreements [Line Items]
Research and development costs	$ 500

Common Stock and Noncontrolling Interest in Subsidiaries - Additional Information (Details) - USD ($)		1 Months Ended									3 Months Ended
	May 28, 2020	Mar. 31, 2022	Jul. 31, 2021	Jun. 30, 2021	Dec. 31, 2020	Nov. 30, 2020	Aug. 31, 2020	May 31, 2020	Apr. 30, 2020	Feb. 28, 2019	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Common stock, shares authorized		150,000,000									150,000,000		150,000,000
Dividends declared		$ 0									$ 0
Common stock, voting rights											Each share of common stock entitles the holder to one vote and to receive dividends when and if declared by the board of directors of the Company.
Shares sold/issued		44,660,026									44,660,026		44,292,102
Losses attributed to noncontrolling interests											$ (794,000)	$ 1,489,000
Note Purchase Agreement
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Issuance of convertible promissory note		$ 3,200,000
Common Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Additional shares issued												13,685,000
License Agreement between Amber and Massachusetts Institute of Technology
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares sold/issued				153,229					400,132
License Agreement between Amber and Massachusetts Institute of Technology \| Common Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Additional consideration received				$ 0					$ 0
Taiho Ventures, LLC \| Note Purchase Agreement
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Issuance of convertible promissory note		800,000
Maximum \| Note Purchase Agreement
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Convertible promissory note to be issued		$ 6,000,000.0
Series A Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares issued				3,000,000
Gross proceeds				$ 3,000,000.0
Cullinan Amber Corp \| Series A Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares issued									3,000,000
Gross proceeds									$ 3,000,000.0
Closing price per share									$ 1.00
Cullinan Amber Corp \| Series A Preferred Stock \| Maximum
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Sale of stock									9,000,000
Cullinan Apollo Corp
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Losses attributed to noncontrolling interests											0	$ 0
Cullinan Florentine Corp \| DFKZ and UFE Anti-dilution Shares
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Additional shares issued			0
Cullinan Florentine Corp \| HLBV
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Losses attributed to noncontrolling interests											$ 0	0
Cullinan Florentine Corp \| Tubingen License Agreement
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares sold/issued							725,118
Cullinan Florentine Corp \| Tubingen License Agreement \| Common Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Additional consideration received							$ 0
Additional shares issued					381,810
Cullinan Florentine Corp \| Tubingen License Agreement \| Common Stock \| DFKZ and UFE Anti-dilution Shares
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Additional consideration received					$ 0
Cullinan Florentine Corp \| Series A Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Gross proceeds					$ 6,000,000.0		$ 6,000,000.0
Sale of stock							6,000,000
Closing price per share							$ 1.00
Additional shares issued					6,000,000
Cullinan Florentine Corp \| Series A Preferred Stock \| Maximum
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Sale of stock							6,000,000
Cullinan Florentine Corp \| Series B Preferred Units
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Gross proceeds			$ 8,100,000
Additional shares issued			7,500,000
MICA
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares sold/issued					3,367,804
Shares price per share					$ 0.23
Equity at acquisition	$ 12,800,000
Aggregate purchase price					$ 800,000
Ownership interest percentage				45.00%							54.00%
MICA \| HLBV
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Losses attributed to noncontrolling interests											$ 500,000	200,000
MICA \| Series A Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Gross proceeds											8,800,000	$ 1,200,000
Additional purchased Preferred stock											$ 10,000,000.0
Additional shares issued				5,385,787
Purchase of shares											6,732,232	878,118
MICA \| Series A Senior Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares issued								6,088,282
Gross proceeds				$ 7,100,000
Shares price per share								$ 1.31
Additional shares issued				702,495
Number of share purchased as part of asset acquisition								5,385,787
Equity at acquisition	7,100,000
MICA \| Series A Senior Preferred Stock \| Certain Existing Shareholders [Member]
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Gross proceeds				$ 900,000
MICA \| Junior Preferred and Common Stockholders \| Noncontrolling Interest in Subsidiaries
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Equity at acquisition	$ 5,700,000
Cullinan Pearl Corp \| HLBV
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Losses attributed to noncontrolling interests											$ 300,000	$ 1,700,000
Cullinan Pearl Corp \| Subscription Agreement between Company and Pearl \| Common Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares price per share						$ 0.44
Aggregate purchase price						$ 1,200,000
Purchase of shares						2,730,227
Cullinan Pearl Corp \| Series A Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Gross proceeds							$ 9,000,000.0
Shares sold/issued							9,000,000
Cullinan Pearl Corp \| Series A Preferred Stock \| Taiho Ventures, LLC
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Gross proceeds										$ 14,000,000.0
Shares sold/issued										14,000,000
Shares price per share										$ 1.00
Cullinan Pearl Corp \| Series A Preferred Stock \| Taiho License Agreement
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares sold/issued							1,206,000			1,860,000
Additional consideration received							$ 0
Aggregate purchase price										$ 0
Cullinan Pearl Corp \| Series A Preferred Stock \| Maximum \| Taiho Ventures, LLC
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares sold/issued										23,000,000

Equity-Based Compensation - Schedule of Equity-based Compensation Expense Categories In Consolidated Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total equity-based compensation	$ 6,565	$ 3,508
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total equity-based compensation	2,660	1,569
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total equity-based compensation	$ 3,905	$ 1,939

Related Party Transactions - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Related Party Transaction [Line Items]
Royalty percentage		1.00%
Royalties under obligation		$ 0		$ 0
Globeways Holdings Limited \| 2020 Consulting Agreement
Related Party Transaction [Line Items]
Related party transaction, description of transaction		In April 2020, the Company entered into a consulting agreement (the Globeways Agreement) with Globeways Holdings Limited, or Globeways. Globeways and entities affiliated with F2 Ventures beneficially own in the aggregate greater than five percent of the Company’s outstanding shares and Globeways is beneficially owned by a member of the Company’s board of directors.
Consulting fee per month	$ 25,000
MPM Oncology Charitable Foundation, Inc.
Related Party Transaction [Line Items]
Royalty percentage		0.50%
UBS Optimus Foundation
Related Party Transaction [Line Items]
Royalty percentage			0.50%
Maximum \| Globeways Holdings Limited \| 2020 Consulting Agreement
Related Party Transaction [Line Items]
Consulting fee		$ 0	$ 100,000

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income tax expense/(benefit)	$ 19,568	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Commitment and Contingencies (Additional Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Indemnification Agreement [Member]
Loss Contingencies [Line Items]
Accrued Liabilities	$ 0	$ 0

Leases - Additional Information (Details) - ft²	1 Months Ended	3 Months Ended
Leases - Additional Information (Details) - ft²	Dec. 31, 2017	Mar. 31, 2022
Lessee Lease Description [Line Items]
Operating lease commence date	Feb. 01, 2018
Operating lease expiration date		Jun. 30, 2024
Massachusetts
Lessee Lease Description [Line Items]
Operating lease rentable area	7,531

Leases - Components of Lease Costs (Details) $ in Thousands	3 Months Ended
Leases - Components of Lease Costs (Details) $ in Thousands	Mar. 31, 2022 USD ($)
Leases [Abstract]
Operating Lease, Cost	$ 147
Short-term Lease, Cost	0
Variable Lease, Cost	$ 0

Leases - Supplemental Cash Flow Information Relating to Leases (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Leases [Abstract]
Operating Lease Payments Proceeds	$ 151
ROU asset obtained in exchange for an operating lease liability	$ 1,311

Leases - Summary of Future Minimum Payments Due Under Operating Lease (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Operating Lease Liabilities Payments Due [Abstract]
Remainder of 2022	$ 457
2023	618
2024	313
Future minimum payments due under operating lease	1,388
Less: imputed interest	(133)
Total lease liabilities at present value	1,255
Lease liabilities, current	519	$ 0
lease liabilities, non-current	$ 736	$ 0

Leases - Summary of Weighted Average Remaining Lease Terms and Discount Rates (Details)	Mar. 31, 2022
Leases [Abstract]
Weighted-average remaining lease term (years)	2 years 3 months 18 days
Weighted-average discount rate	9.50%

Employee Benefit Plan - Additional Information (Details) - 401(K) Plan - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Expense relating to matching contribution	$ 0.1
Maximum
Defined Benefit Plan Disclosure [Line Items]
Expense relating to matching contribution		$ 0.1

Net Loss per Share - Summary of Calculation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net loss attributable to common stockholders of Cullinan	$ (12,098)	$ (70)
Denominator
Total weighted-average shares used in computing net loss per share, basic and diluted	44,431,657	41,977,336
Net Loss per Share:	$ (0.27)	$ (0.00)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Net Loss per Share - Summary of Outstanding Equity Instruments Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from computation of diluted net loss per share (in shares)	10,065,814	6,853,465
Restricted Stock Awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from computation of diluted net loss per share (in shares)	73,448	242,411
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from computation of diluted net loss per share (in shares)	9,985,444	6,600,953
Estimated Shares Issuable Under The ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares excluded from computation of diluted net loss per share (in shares)	6,922	10,101

Subsequent Events (Additional Information) (Details) - Subsequent Event [Member] $ in Millions	1 Months Ended
	May 31, 2022 USD ($)
Subsequent Event [Line Items]
Receive upfront payment from party	$ 275.0
Additional receive payments from the party	$ 130.0
Development Costs, Percentage	50.00%
Future potential pre-tax, Percentage	50.00%