0001193125-26-330672 | 10-Q | XBRL Viewer

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Debt - Schedule of Interest Expense Recognized and Effective Interest Rates (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Interest Costs Incurred [Abstract]
Contractual interest expense	$ 2,596	$ 0	$ 3,029	$ 0
Amortization of debt discount and issuance costs	728	0	848	0
Total interest and amortization expense	$ 3,324	$ 0	$ 3,877	$ 0
Effective interest rate	0.50%	0.00%	0.50%	0.00%

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2026	Jun. 30, 2025
Pay vs Performance Disclosure
Net Income (Loss)	$ (91,154)	$ (122,931)	$ (208,549)	$ (135,996)	$ (214,085)	$ (344,545)

- Definition

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

+ References

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+ Details

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025	Jun. 30, 2025	Dec. 31, 2024
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 291,337	$ 347,559	$ 193,618
Prepaid expenses and other current assets	377		3,514
Restricted cash	7,629	7,629	8,006
Cash, cash equivalents and restricted cash at end of period	$ 299,343	$ 359,078	$ 205,138	$ 309,776

Share Capital - Additional Information (Detail) SFr / shares in Units, $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended	6 Months Ended		12 Months Ended
	May 19, 2025 SFr / shares shares	Oct. 31, 2025 USD ($)	Jan. 31, 2021 USD ($)	Jun. 30, 2025 USD ($) $ / shares shares	Jun. 30, 2026 USD ($) $ / shares shares	Jun. 30, 2025 USD ($) $ / shares shares	Dec. 31, 2025 USD ($) $ / shares	Jun. 30, 2026 SFr / shares shares	Jun. 30, 2026 $ / shares shares	Dec. 31, 2025 SFr / shares shares	Jun. 08, 2023 CHF (SFr) SFr / shares
Class of Stock [Line Items]
Common shares, nominal value \| SFr / shares								SFr 0.03		SFr 0.03	SFr 0.03
Proceeds from issuance of common shares					$ (722)	$ 8,494
Registered share capital \| shares								98,599,444	98,599,444
Registered common shares \| shares								9,366,947	9,366,947
Common shares employee equity incentive plans \| shares								17,686,403	17,686,403
2021 ATM [Member]
Class of Stock [Line Items]
Average issue price of common shares \| $ / shares							$ 74.77
Proceeds from issuance of common shares							$ 592,200
Equity issuance costs							7,800
Common shares issued \| shares										8,000,000
Stamp taxes on issuance of common stock							$ 5,900
Number of remaining common shares available \| shares										0
Capital Band [Member]
Class of Stock [Line Items]
Common shares issued \| shares								18,795,173	18,795,173
Maximum [Member]
Class of Stock [Line Items]
Common stock share capital value \| SFr											SFr 3,521,838.51
Sales Agreement With Jefferies LLC [Member] \| 2021 ATM [Member]
Class of Stock [Line Items]
Average issue price of common shares \| $ / shares				$ 54.33		$ 54.33
Proceeds from issuance of common shares				$ 8,700		$ 8,700
Equity issuance costs				$ 100		$ 100
Issuance of common shares \| shares				200,000		200,000
Stamp taxes on issuance of common stock				$ 100		$ 100
Sales Agreement With Jefferies LLC [Member] \| 2025 ATM [Member]
Class of Stock [Line Items]
Aggregate estimated gross proceeds					$ 557,200
Average issue price of common shares \| $ / shares					$ 60.81
Proceeds from issuance of common shares					$ 42,300
Equity issuance costs					500
Common shares issued \| shares								0	0
Common shares issued \| shares								700,000	700,000
Stamp taxes on issuance of common stock					$ 400
Sales Agreement With Jefferies LLC [Member] \| Maximum [Member] \| 2021 ATM [Member]
Class of Stock [Line Items]
Aggregate estimated gross proceeds			$ 600,000
Sales Agreement With Jefferies LLC [Member] \| Maximum [Member] \| 2025 ATM [Member]
Class of Stock [Line Items]
Aggregate estimated gross proceeds		$ 600,000
Sirius Therapeutics [Member]
Class of Stock [Line Items]
Common shares, nominal value \| SFr / shares	SFr 0.03
Share price \| $ / shares									$ 38
Issuance of common shares \| shares	1,842,105				1,842,105

Property and Equipment, net

6 Months Ended

Jun. 30, 2026

Property, Plant and Equipment [Abstract]

Property and Equipment, net

4. Property and Equipment, net

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


	As of
	June 30,			December 31,
	2026			2025
Computer equipment	$	4,152		$	4,152
Furniture, fixtures and other		8,554			8,554
Laboratory equipment		44,950			43,575
Leasehold improvements		146,788			146,667
Construction work in process		3,217			3,955
Total property and equipment, gross		207,661			206,903
Accumulated depreciation		(99,593	)		(91,052	)
Total property and equipment, net	$	108,068		$	115,851

Depreciation expense for the three and six months ended June 30, 2026 was $4.3 million and $8.6 million, respectively. Depreciation expense for the three and six months ended June 30, 2025 was $4.6 million and $9.3 million, respectively.

Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2026

Investments, Debt and Equity Securities [Abstract]

Summary of Cash Equivalents and Marketable Securities Recorded at Fair Value

The following table summarizes cash equivalents and marketable securities held at June 30, 2026 and December 31, 2025 (in thousands), which are recorded at fair value. The table below excludes $260.7 million and $295.4 million of cash at June 30, 2026 and December 31, 2025, respectively.


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
June 30, 2026
Cash equivalents:
Money market funds	$	30,639	$	—	$	—		$	30,639
Total cash equivalents		30,639		—		—			30,639
Marketable securities:
Corporate debt securities		1,374,062		579		(3,367	)		1,371,274
Certificates and term deposits		322,376		—		—			322,376
Government-sponsored enterprise securities		302,462		4		(1,893	)		300,573
Commercial paper		68,390		—		(34	)		68,356
Total marketable debt securities		2,067,290		583		(5,294	)		2,062,579
Corporate equity securities		7,500		2,936		—			10,436
Total marketable securities		2,074,790		3,519		(5,294	)		2,073,015
Total cash equivalents and marketable securities	$	2,105,429	$	3,519	$	(5,294	)	$	2,103,654
December 31, 2025
Cash equivalents:
Money market funds	$	37,255	$	—	$	—		$	37,255
Commercial paper		14,896		—		(4	)		14,892
Total cash equivalents		52,151		—		(4	)		52,147
Marketable securities:
Corporate debt securities		1,152,319		3,827		(181	)		1,155,965
Certificates of deposit		101,100		—		—			101,100
Government-sponsored enterprise securities		304,259		1,054		(15	)		305,298
Commercial paper		49,432		28		—			49,460
Total marketable debt securities		1,607,110		4,909		(196	)		1,611,823
Corporate equity securities		7,500		8,946		—			16,446
Total marketable securities		1,614,610		13,855		(196	)		1,628,269
Total cash equivalents and marketable securities	$	1,666,761	$	13,855	$	(200	)	$	1,680,416

Summary of Net Unrealized Gain (Loss) Recorded on Marketable Debt and Equity Securities

The following table summarizes the net unrealized gain (loss) recorded on marketable debt and equity securities during the three and six months ended June 30, 2026 and 2025 (in millions):


	Three Months Ended						For the Six Months Ended
	June 30,						June 30,
	2026			2025			2026			2025
Unrealized (loss) gain recorded on marketable debt securities		(2.7	)		(0.2	)		(9.4	)		2.1
Unrealized gain (loss) recorded on marketable equity securities		6.1			1.8			(6.0	)		(6.4	)

The following table summarizes the net unrealized gain (loss) position of the Company’s marketable debt and equity securities as of June 30, 2026 and December 31, 2025 (in millions):


	June 30, 2026			December 31, 2025
Unrealized (loss) gain position of marketable debt securities	$	(4.7	)	$	4.7
Unrealized gain position of marketable equity securities		2.9			8.9

Summary of Aggregate Fair Value of Marketable Debt Securities

The following table summarizes the aggregate fair value of marketable debt securities that were in an unrealized loss position as of June 30, 2026 and December 31, 2025 by the length of time the security has been in a loss position (in millions):


	June 30, 2026		December 31, 2025
Debt securities in an unrealized loss position for 12 months or less	$	1,292.3	$	193.8
Debt securities in an unrealized loss position for more than 12 months		—		—
Total debt securities in an unrealized loss position	$	1,292.3	$	193.8

Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2026

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

During the three and six months ended June 30, 2026 and 2025, the Company recognized the following stock-based compensation expense (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Research and development	$	7,840	$	7,805	$	15,694	$	17,537
General and administrative		9,476		9,802		17,946		20,282
Total	$	17,316	$	17,607	$	33,640	$	37,819

Summary of Stock Option Activity

The following table summarizes stock option activity for the six months ended June 30, 2026:


	Shares			Weighted- average exercise price per share
Outstanding at December 31, 2025		6,747,835		$	56.82
Granted		875,531			47.58
Exercised		(326,058	)		44.29
Cancelled or forfeited		(436,099	)		66.24
Outstanding at June 30, 2026		6,861,209		$	55.64
Exercisable at June 30, 2026		4,694,440		$	57.66
Vested and expected to vest at June 30, 2026		6,861,209		$	55.64

Summary of Restricted Stock Activity

The following table summarizes restricted stock activity for the six months ended June 30, 2026:


	Shares			Weighted- Average Grant Date Fair Value
Unvested balance at December 31, 2025		1,965,567		$	52.16
Granted		689,956			48.28
Vested		(429,134	)		53.28
Cancelled or forfeited		(169,286	)		50.69
Unvested balance at June 30, 2026		2,057,103		$	50.69

Significant Contracts - Additional Information (Detail)		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
Significant Contracts - Additional Information (Detail)	May 19, 2025 USD ($) shares	May 31, 2024 USD ($)	Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($) shares	Jun. 30, 2025 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2026 SFr / shares	Jun. 30, 2026 USD ($) shares	Dec. 31, 2025 SFr / shares	Dec. 31, 2025 USD ($) shares	May 19, 2025 SFr / shares	May 19, 2025 USD ($) $ / shares shares	Jun. 08, 2023 SFr / shares	Dec. 31, 2021
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Current deferred revenue									$ 15,189,000		$ 15,771,000
Collaboration Expense			$ 40,272,000	$ 45,153,000	$ 86,221,000	$ 102,662,000
Common stock, shares issued \| shares									96,761,275		96,009,657
Common shares, nominal value \| SFr / shares								SFr 0.03		SFr 0.03				SFr 0.03
Research and development			67,152,000	69,894,000	135,726,000	142,378,000
A&R Vertex JDCA [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Percentage of net profits and net losses															40.00%
Vertex Pharmaceuticals Incorporated and Certain of its Subsidiaries [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue			0	0	0	0
Collaboration Expense			40,300,000	45,200,000	86,200,000	102,700,000
Vertex Pharmaceuticals Incorporated and Certain of its Subsidiaries [Member] \| Collaboration Target Options [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone payment receivable									$ 410,000,000
Vertex Pharmaceuticals Incorporated and Certain of its Subsidiaries [Member] \| A&R Vertex JDCA [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Percentage of net profits and net losses															60.00%
Current payment due							$ 20,000,000
Vertex Pharmaceuticals Incorporated and Certain of its Subsidiaries [Member] \| Non-Ex License Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone payment receivable									125,000,000
Vertex Pharmaceuticals Incorporated and Certain of its Subsidiaries [Member] \| 2019 Collaborative Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Maximum potential future payments					775,000,000
Vertex Pharmaceuticals Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Proceeds from letter agreement		$ 43,000,000
Net proceeds from transfer		42.00%
Transaction price allocated to remaining performance obligations									12,300,000
Reimbursements from research and license agreements			3,000,000	$ 600,000	4,200,000	$ 700,000
Vertex Pharmaceuticals Inc [Member] \| 2019 Collaborative Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Current deferred revenue									$ 12,300,000
Sirius Therapeutics [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Reimbursements from research and license agreements			500,000		$ 700,000
Upfront cash payment													$ 25,000,000
Common stock, shares issued \| shares													70,000,000
Issuance of common shares \| shares	1,842,105				1,842,105
Common shares, nominal value \| SFr / shares												SFr 0.03
Share issued price \| $ / shares													$ 38
One time payment per option	$ 10,000,000
Future development regulatory and sales milestone payment	300,000,000
Research and development			$ 3,400,000		$ 5,000,000
Sirius Therapeutics [Member] \| Maximum [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestones aggregate payment	$ 87,500,000				87,500,000
Future development regulatory and sales milestone payment					$ 300,000,000

Marketable Securities - Summary of Cash Equivalents and Marketable Securities Recorded at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Marketable Securities [Line Items]
Cash equivalents, amortized cost	$ 30,639	$ 52,151
Cash equivalents, gross unrealized gains	0	0
Cash equivalents, gross unrealized losses	0	(4)
Cash equivalents, fair value	30,639	52,147
Marketable securities, amortized cost	2,067,290	1,607,110
Total marketable securities, amortized cost	2,074,790	1,614,610
Marketable securities, gross unrealized gains	583	4,909
Total marketable securities, gross unrealized gains	3,519	13,855
Marketable securities, gross unrealized losses	(5,294)	(196)
Total marketable securities, gross unrealized losses	(5,294)	(196)
Marketable securities, fair value	2,062,579	1,611,823
Total marketable securities, fair value	2,073,015	1,628,269
Cash equivalents and marketable securities, amortized cost	2,105,429	1,666,761
Cash equivalents and marketable securities, gross unrealized gains	3,519	13,855
Cash equivalents and marketable securities, gross unrealized losses	(5,294)	(200)
Cash equivalents and marketable securities, fair value	2,103,654	1,680,416
Money Market Funds [Member]
Marketable Securities [Line Items]
Cash equivalents, amortized cost	30,639	37,255
Cash equivalents, gross unrealized gains	0	0
Cash equivalents, gross unrealized losses	0	0
Cash equivalents, fair value	30,639	37,255
Commercial Paper [Member]
Marketable Securities [Line Items]
Cash equivalents, amortized cost		14,896
Cash equivalents, gross unrealized gains		0
Cash equivalents, gross unrealized losses		(4)
Cash equivalents, fair value		14,892
Marketable securities, amortized cost	68,390	49,432
Marketable securities, gross unrealized gains	0	28
Marketable securities, gross unrealized losses	(34)	0
Marketable securities, fair value	68,356	49,460
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Marketable securities, amortized cost	1,374,062	1,152,319
Marketable securities, gross unrealized gains	579	3,827
Marketable securities, gross unrealized losses	(3,367)	(181)
Marketable securities, fair value	1,371,274	1,155,965
Certificates of Deposit [Member]
Marketable Securities [Line Items]
Marketable securities, amortized cost	322,376	101,100
Marketable securities, gross unrealized gains	0	0
Marketable securities, gross unrealized losses	0	0
Marketable securities, fair value	322,376	101,100
Government-sponsored Enterprise Securities [Member]
Marketable Securities [Line Items]
Marketable securities, amortized cost	302,462	304,259
Marketable securities, gross unrealized gains	4	1,054
Marketable securities, gross unrealized losses	(1,893)	(15)
Marketable securities, fair value	300,573	305,298
Corporate Equity Securities [Member]
Marketable Securities [Line Items]
Total marketable securities, amortized cost	7,500	7,500
Total marketable securities, gross unrealized gains	2,936	8,946
Total marketable securities, gross unrealized losses	0	0
Total marketable securities, fair value	$ 10,436	$ 16,446

Property and Equipment, net - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 207,661	$ 206,903
Accumulated depreciation	(99,593)	(91,052)
Total property and equipment, net	108,068	115,851
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	4,152	4,152
Furniture, Fixtures and Other [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	8,554	8,554
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	44,950	43,575
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	146,788	146,667
Construction Work in Process [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 3,217	$ 3,955

Marketable Securities - Summary of Aggregate Fair Value of Marketable Debt Securities (Detail) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Debt securities in an unrealized loss position for 12 months or less	$ 1,292.3	$ 193.8
Debt securities in an unrealized loss position for more than 12 months	0.0	0.0
Total debt securities in an unrealized loss position	$ 1,292.3	$ 193.8

Marketable Securities - Summary of Net Unrealized Gain (Loss) Recorded on Marketable Debt and Equity Securities (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Marketable Debt Securities [Member]
Marketable Securities [Line Items]
Unrealized (loss) gain recorded on marketable securities	$ (2.7)	$ (0.2)	$ (9.4)	$ 2.1
Unrealized (loss) gain position of marketable debt securities	(4.7)		(4.7)		$ 4.7
Marketable Equity Securities [Member]
Marketable Securities [Line Items]
Unrealized (loss) gain recorded on marketable securities	6.1	$ 1.8	(6.0)	$ (6.4)
Unrealized gain position of marketable equity securities	$ 2.9		$ 2.9		$ 8.9

Insider Trading Arrangements

3 Months Ended

Jun. 30, 2026

Trading Arrangements, by Individual

Material Terms of Trading Arrangement

Item 5. Other Information.

(a) Not applicable.

(b) Not applicable.

(c) From time to time, our officers (as defined in Rule 16a–1(f)) and directors may enter into Rule 10b5-1 or non-Rule 10b5-1 trading arrangements (as each such term is defined in Item 408 of Regulation S-K). During the three months ended June 30, 2026, our officers and directors took the following actions with respect to Rule 10b5-1 trading agreements:


Name (Title)	Action Taken (Date of Action)	Type of Trading Arrangement	Nature of Trading Arrangement	Duration of Trading Arrangement	Aggregate Number of Securities
James R. Kasinger (General Counsel and Secretary)	Adoption (May 6, 2026)	Trading plan intended to satisfy the affirmative defense conditions of Securities Exchange Act Rule 10b5-1(c).	Sale of the Company’s common stock pursuant to the terms of the plan.	Active through May 31, 2027		93,632


Raju Prasad, Ph.D. (Chief Financial Officer)	Adoption (June 9, 2026)	Trading plan intended to satisfy the affirmative defense conditions of Securities Exchange Act Rule 10b5-1(c).	Sale of the Company’s common stock pursuant to the terms of the plan.	Active through May 31, 2027		14,565

James R. Kasinger [Member]

Trading Arrangements, by Individual

Name

James R. Kasinger

Title

General Counsel and Secretary

Rule 10b5-1 Arrangement Adopted

true

May 6, 2026

May 31, 2027

390 days

93,632

Trading Arrangements, by Individual

Name

Raju Prasad

Title

Chief Financial Officer

Rule 10b5-1 Arrangement Adopted

true

June 9, 2026

May 31, 2027

356 days

14,565

Segment Information (Tables)

6 Months Ended

Jun. 30, 2026

Segment Reporting [Abstract]

Schedule of Reportable Segment Profit and Loss, Including Significant Expense Categories, Attributable to the Company's Reportable Segment

The following table illustrates information about segment revenue, significant segment expenses and segment operating loss for the periods presented (in thousands):


	Three Months Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Revenue:
Collaboration revenue	$	10,000		$	—		$	11,000		$	—
Grant revenue		181			892			639			1,757
Less1:
Research and development expense2		53,708			59,232			110,737			119,565
Acquired in-process research and development3		2,473			96,253			2,473			96,253
General and administrative expense4		5,957			6,840			12,553			13,357
Collaboration expense, net - Vertex5		40,272			45,153			86,221			102,662
Collaboration expense, net - Sirius6		3,444			500			4,950			500
Stock-based compensation expense		17,316			17,607			33,640			37,819
Depreciation expense		4,280			4,631			8,582			9,349
Other segment items7		(26,115	)		(20,775	)		(33,432	)		(33,203	)
Segment net loss		(91,154	)		(208,549	)		(214,085	)		(344,545	)
Reconciliation of profit or loss:
Adjustments or reconciling items		—			—			—			—
Consolidated net loss		(91,154	)		(208,549	)		(214,085	)		(344,545	)

(1) The significant expense categories and amounts align with the segment-level information that is regularly provided to the CODM.

(2) Research and development expense for the three and six months ended June 30, 2026 excludes $7.8 million and $15.7 million of stock-based compensation expense, respectively, and $2.2 million and $4.4 million of depreciation expense, respectively. Research and development expense for the three and six months ended June 30, 2025 excludes

$7.8 million and $17.5 million of stock-based compensation expense, respectively, and $2.4 million and $4.8 million of depreciation expense, respectively.

(3) Acquired in-process research and development expense for the three and six months ended June 30, 2026 was not material. The $96.3 million acquired in-process research and development expense for the three and six months ended June 30, 2025 is attributable to the costs incurred upon entering the Sirius Agreement, as described in Note 6 of the notes to our unaudited condensed consolidated financial statements included in this Quarterly Report on Form 10-Q.

(4) General and administrative expense for the three and six months ended June 30, 2026 excludes $9.5 million and $17.9 million of stock-based compensation expense, respectively, and $2.1 million and $4.2 million of depreciation expense, respectively. General and administrative expense for the three and six months ended June 30, 2025 excludes $9.8 million and $20.3 million of stock-based compensation expense, respectively, and $2.3 million and $4.6 million of depreciation expense, respectively.

(5) Collaboration costs specific to the Vertex Hemoglobinopathy Agreements (as defined in Note 6) accounted for under ASC 808 are presented within “collaboration expense, net” in the condensed consolidated statements of operations and comprehensive loss.

(6) In the second quarter of 2025, the Company entered into the Sirius Agreement (as defined in Note 6). Collaboration costs, net of reimbursements, related to the Sirius Collaboration Products under the Sirius Agreement are presented within “research and development expense” in the condensed consolidated statements of operations and comprehensive loss. In the first quarter of 2026, the significant expense categories reviewed by the CODM were updated to include collaboration costs, net of reimbursements, associated with the Sirius Collaboration Products. As a result, the Company recast segment amounts for the three and six months ended June 30, 2025 to reflect the updated significant expense categories.

(7) Other segment items include interest income (expense), net, the change in fair value of corporate equity securities and income tax expense.

Property and Equipment, net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 4.3	$ 4.6	$ 8.6	$ 9.3

Debt - Schedule of Outstanding Balances of Notes (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Debt Disclosure [Abstract]
Principal	$ 600,000	$ 0
Unamortized debt discount and issuance costs	(13,802)	0
Net carrying amount	$ 586,198	$ 0

- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References + Details

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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+ Details

Debt (Tables)

6 Months Ended

Jun. 30, 2026

Debt Disclosure [Abstract]

Schedule of Outstanding Balances of Notes

The outstanding balances of the Notes consisted of the following (in thousands):


	June 30, 2026			December 31, 2025
Principal	$	600,000		$	—
Unamortized debt discount and issuance costs		(13,802	)		—
Net carrying amount	$	586,198		$	—

Schedule of Interest Expense Recognized and Effective Interest Rates

The following table sets forth the total interest expense recognized and effective interest rates related to the Notes for the periods presented (in thousands):


	Three Months Ended June 30					Six Months Ended June 30
	2026			2025		2026			2025
Contractual interest expense	$	2,596		$	—	$	3,029		$	—
Amortization of debt discount and issuance costs		728			—		848			—
Total interest and amortization expense	$	3,324		$	—	$	3,877		$	—
Effective interest rate		0.5	%		—		0.5	%		—

Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2026
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements are unaudited and have been prepared by the Company in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP. The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company views its operations and manages its business in one operating segment, which is the business of discovering, developing and commercializing therapies. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These interim financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the financial position and results of operations for the three and six-month interim periods ended June 30, 2026 and 2025. Certain prior period amounts have been reclassified to conform to the current presentation. Specifically, the Company reclassified “Sales of marketable securities” in the condensed consolidated statements of cash flows, which were classified within “Maturities of marketable securities” in prior periods. As a result, no subtotals in the prior year condensed consolidated financial statements were impacted. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These interim financial statements should be read in conjunction with the audited financial statements for the year ended December 31, 2025, which are contained in the 2025 Annual Report on Form 10-K filed with the Securities and Exchange Commission, or the SEC, on February 12, 2026.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates, which include, but are not limited to, revenue recognition, equity-based compensation expense and reported amounts of expenses during the period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions. Changes in estimates are reflected in reported results in the period in which they become known.
New Accounting Pronouncements - Recently Adopted	In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures, and in January 2025, the FASB issued ASU 2025-01, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures: Clarifying the Effective Date. ASU 2024-03 requires disclosure of additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. ASU 2024-03, as clarified by ASU 2025-01, is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the disclosure requirements related to this new standard.

- Definition

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+ Details

Fair Value Measurements - Aggregate Face Values and the Fair values of the Notes (Detail) - Convertible Senior Notes Due 2031 [Member] - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 16, 2026	Dec. 31, 2025
Fair Value, Option, Quantitative Disclosures [Line Items]
Aggregate Face Values	$ 600,000	$ 600,000	$ 0
Estimated Fair Values	$ 636,360		$ 0

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)(i)
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Stock-based Compensation - Summary of Stock Option Activity (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2026
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract]
Shares, Outstanding, Beginning Balance	6,747,835
Shares, Granted	875,531
Shares, Exercised	(326,058)
Shares, Cancelled or forfeited	(436,099)
Shares, Outstanding, Ending Balance	6,861,209
Shares, Exercisable	4,694,440
Shares, Vested and expected to vest	6,861,209
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 56.82
Weighted-Average Exercise Price, Granted	47.58
Weighted-Average Exercise Price, Exercised	44.29
Weighted-Average Exercise Price, Cancelled or forfeited	66.24
Weighted-Average Exercise Price, Outstanding, Ending Balance	55.64
Weighted-Average Exercise Price, Exercisable	57.66
Weighted-Average Exercise Price, Vested and expected to vest	$ 55.64

Commitments and Contingencies

6 Months Ended

Jun. 30, 2026

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

7. Commitments and Contingencies

Leases

Refer to Note 7 to the consolidated financial statements in the Company’s 2025 Annual Report on Form 10-K filed with the SEC on February 12, 2026 for discussion of the Company’s lease arrangements.

Litigation

In the ordinary course of business, the Company is or has been from time to time involved in lawsuits, investigations, proceedings and threats of litigation related to, among other things, the Company’s intellectual property estate (including certain in-licensed intellectual property), commercial arrangements and other matters. Such proceedings may include quasi-litigation, inter partes administrative proceedings in the U.S. Patent and Trademark Office and the European Patent Office or patent offices in other countries, involving the Company’s intellectual property estate including certain in-licensed intellectual property. For example, in the fourth quarter of 2025, ToolGen, Inc., or ToolGen, initiated a lawsuit against the Company and other third parties alleging patent infringement by CASGEVY of a ToolGen patent relating to CRISPR/Cas9 gene editing technology. The Company was subsequently dismissed from the lawsuit as a defendant in April 2026 without prejudice. The outcome of any of the foregoing is inherently uncertain. In addition, litigation and related matters are costly and may divert the attention of Company’s management and other resources that would otherwise be engaged in other activities. If the Company is unable to prevail in any such proceedings, the Company’s business, results of operations, liquidity and financial condition could be adversely affected.

Letters of Credit

The Company had restricted cash of $8.0 million and $11.5 million as of June 30, 2026 and December 31, 2025, respectively, representing letters of credit securing the Company’s obligations under certain leased facilities. The letters of credit are secured by cash held in a restricted depository account, with $0.4 million and $3.9 million included in “Prepaid expenses and other current assets” and $7.6 million and $7.6 million included in “Restricted cash” on the Company’s condensed consolidated balance sheets as of June 30, 2026 and December 31, 2025, respectively.

Research, Manufacturing, License and Intellectual Property Agreements

The Company has engaged several research institutions and companies to identify new delivery strategies and applications of the Company’s gene editing technology. The Company is also a party to a number of license agreements which require significant upfront payments and may be required to make future royalty payments and potential milestone payments from time to time. In addition, the Company is also a party to intellectual property agreements, which require maintenance and milestone payments from time to time. Further, the Company is a party to a number of manufacturing agreements that require upfront payments for the future performance of services.

In connection with these agreements, on a product-by-product basis, the counterparties are eligible to receive up to low eight-digit potential payments upon specified research, development and regulatory milestones. In addition, on a product-by-product basis, the counterparties are eligible to receive potential commercial milestone payments based on specified annual sales thresholds. The potential payments are low single-digit percentages of the specified annual sales thresholds. The counterparties are also eligible to receive low single-digit royalties on future net sales.

In 2025, a third-party licensor formally engaged with the Company regarding certain matters under their intellectual property contracts with the Company that may lead to further actions that could result in additional amounts being owed by the Company to such third party. The Company determined that it was probable that a loss was incurred as of December 31, 2025 and, based on the Company’s best estimate of the loss, the Company recorded incremental research and development expenses of $13.0 million in the fourth quarter of 2025. The total liability associated with the contingent loss as of December 31, 2025 was $14.5 million. The Company reassessed the liability as of June 30, 2026 and recorded incremental research and development expenses of $3.8 million. The total liability associated with the contingent loss as of June 30, 2026 was $18.3 million. The liability is primarily included within other current liabilities on the condensed consolidated balance sheets as of June 30, 2026 and December 31, 2025. The Company is unable to provide an estimate of a range of loss, and the ultimate resolution of the matter could result in a material charge in excess of the amount accrued as of June 30, 2026. The Company will reassess the contingent liability and matters relating thereto as necessary or appropriate.

Vertex is eligible to receive up to $395.0 million in potential specified research, development, regulatory and commercial milestones and tiered single-digit percentage royalties on future net sales related to a specified target under an amendment to the 2015 Collaboration Agreement (as such term is defined in Note 6 of the notes to our unaudited condensed consolidated financial statements included in this Quarterly Report on Form 10-Q above). In addition, Vertex has the option to conduct research at its own cost in certain defined areas that, if beneficial to a program under the Vertex Hemoglobinopathy Agreements and the applicable product ultimately achieves regulatory approval, could result in the Company owing Vertex certain milestone payments aggregating to high eight digits, subject to certain limitations on the profitability of the program.

Under the A&R Vertex JDCA for 2022, 2023 and 2024, the Company had an option to defer a portion of its share of costs if spending on the CASGEVY program exceeded specified amounts, which the Company exercised in each such year, resulting in deferred costs of $221.8 million, in the aggregate. Any deferred amounts under the A&R Vertex JDCA are only payable to Vertex as

an offset against future profitability of the CASGEVY program and the amounts payable are capped at a specified maximum amount per year. These deferred costs on the CASGEVY program will be recognized by the Company when recoverability of such deferred amounts by Vertex is probable and the amount can be reasonably estimated. As of June 30, 2026, no contingent payments have been accrued to date.

The Company may be required to make future potential payments to Sirius under the Sirius Agreement defined and described in Note 6 of the notes to our unaudited condensed consolidated financial statements included in this Quarterly Report on Form 10-Q. Potential payments to Sirius include (i) up to $20.0 million in Sirius Option Payments, (ii) up to $300.0 million in certain specified future development, regulatory and sales milestones for the first siRNA Licensed Product relating to each licensed target to achieve the applicable milestones, as well as tiered royalty payments in the mid-single digits to low double digits range on future sales of a commercialized siRNA Licensed Product, and (iii) up to $87.5 million in certain specified future development and regulatory milestones related to the Sirius Collaboration Products. As of June 30, 2026, no contingent payments have been accrued to date.

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended		12 Months Ended
	May 19, 2025	Jun. 30, 2026	Dec. 31, 2025	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Contingencies And Commitments [Line Items]
Research and development expense		$ 67,152		$ 69,894	$ 135,726	$ 142,378
Letters of credit secured by cash held in restricted depository account		377		3,514	377	3,514
Total liability associated with the contingent loss		18,300	$ 14,500		18,300
Restricted cash		7,629	7,629	$ 8,006	7,629	$ 8,006
Deferred Finance Costs, Share Lending Arrangement, Issuance Costs							$ 221,800	$ 221,800	$ 221,800
Contingent payments		0			0
Prepaid Expenses and Other Current Assets [Member]
Contingencies And Commitments [Line Items]
Letters of credit secured by cash held in restricted depository account		400	3,900		400
Sirius Therapeutics [Member]
Contingencies And Commitments [Line Items]
Research and development expense		3,400			5,000
Contingent payments		0			0
Future development regulatory and sales milestone payment	$ 300,000
Sirius Therapeutics [Member] \| Maximum [Member]
Contingencies And Commitments [Line Items]
Future development regulatory and sales milestone payment					300,000
Option payments					20,000
Milestones aggregate payment	$ 87,500				87,500
Letter of Credit [Member]
Contingencies And Commitments [Line Items]
Letters of credit secured by cash held in restricted depository account		8,000	11,500		8,000
2015 Collaboration Agreement [Member] \| Vertex Pharmaceuticals Incorporated and Certain of its Subsidiaries [Member]
Contingencies And Commitments [Line Items]
Milestone payment receivable		$ 395,000			395,000
Intellectual Property [Member]
Contingencies And Commitments [Line Items]
Research and development expense			$ 13,000		$ 3,800

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Income Tax Disclosure [Abstract]
Income tax provision (benefit)	$ 960	$ 1,292	$ 1,799	$ 2,401
Effective income tax rate	(1.10%)	(0.60%)	(0.90%)	(0.70%)

- Definition

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

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+ Details

Stock-based Compensation - Summary of Restricted Stock Activity (Detail) - Restricted Stock [Member]	6 Months Ended
	Jun. 30, 2026 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted common shares, Number of Shares, Beginning Balance \| shares	1,965,567
Unvested restricted common shares, Number of Shares, Granted \| shares	689,956
Unvested restricted common shares, Number of Shares, Vested \| shares	(429,134)
Unvested restricted common shares, Number of Shares, Cancelled or forfeited \| shares	(169,286)
Unvested restricted common shares, Number of Shares, Ending Balance \| shares	2,057,103
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Beginning Balance \| $ / shares	$ 52.16
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Granted \| $ / shares	48.28
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Vested \| $ / shares	53.28
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Cancelled or forfeited \| $ / shares	50.69
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Ending Balance \| $ / shares	$ 50.69

Significant Contracts

6 Months Ended

Jun. 30, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Significant Contracts

6. Significant Contracts

Agreements with Vertex

For purposes of this Note 6 and Note 7, CASGEVY (exagamglogene autotemcel [exa-cel]) is referred to as “CASGEVY”.

2015 collaboration

In 2015, the Company entered into a strategic collaboration, option and license agreement, or the 2015 Collaboration Agreement, with Vertex Pharmaceuticals Incorporated, or Vertex. The 2015 Collaboration Agreement is focused on the use of the Company’s CRISPR/Cas9 gene editing technology to discover and develop potential new treatments aimed at the underlying genetic causes of human disease. The Company and Vertex amended the 2015 Collaboration Agreement in 2017 and 2019 with Amendment No. 1 and Amendment No. 2, respectively, namely to clarify Vertex’s option rights under the 2015 Collaboration Agreement and to modify certain definitions and provisions of the 2015 Collaboration Agreement to make them consistent with the JDA (as defined below) and a strategic collaboration and license agreement from 2019 for the development and commercialization of products for the treatment of Duchenne muscular dystrophy, or DMD, and myotonic dystrophy type 1, or DM1. In 2017, Vertex exercised an option granted to it under the 2015 Collaboration Agreement to obtain a co-exclusive license to develop and commercialize hemoglobinopathy and beta-globin targets, and in 2019, Vertex exercised the remaining options granted to it under the 2015 Collaboration Agreement to exclusively license certain collaboration targets developed under the 2015 Collaboration Agreement.

Hemoglobinopathies collaboration

In 2017, following Vertex’s exercise of its option to obtain a co-exclusive license to develop and commercialize hemoglobinopathy and beta-globin targets, the Company and Vertex entered into a joint development and commercialization agreement, or the JDA, and agreed for potential hemoglobinopathy treatments, including CASGEVY, the Company and Vertex would share equally all research and development costs and worldwide revenues. In 2021, the Company and Vertex amended and restated the JDA, as amended and in effect, from time to time, or the A&R Vertex JDCA, pursuant to which the parties agreed to, among other things, (a) adjust the governance structure for the collaboration and adjust the responsibilities of each party thereunder, whereby Vertex leads and has all decision making (i.e., control) in relation to the CASGEVY program prospectively; (b) adjust the allocation

of net profits and net losses between the parties with respect to CASGEVY only, which will be allocated 40% to the Company and 60% to Vertex, prospectively; and (c) exclusively license (subject to the Company’s reserved rights to conduct certain activities) certain intellectual property rights to Vertex relating to the specified product candidates and products (including CASGEVY) that may be researched, developed, manufactured and commercialized on a worldwide basis under the A&R Vertex JDCA. Additionally, for 2022, 2023, and 2024, the Company had an option to defer a portion of its share of costs under the A&R Vertex JDCA if spending on the CASGEVY program exceeded specified amounts. Any deferred amounts under the A&R Vertex JDCA are only payable to Vertex as an offset against future profitability of the CASGEVY program and the amounts payable are capped at a specified maximum amount per year.

In December 2023, the Company entered into an amendment to the A&R Vertex JDCA, or Amendment No. 1 to the A&R Vertex JDCA, with Vertex related to the global development, manufacturing, and commercialization of CASGEVY. Pursuant to Amendment No. 1 to the A&R Vertex JDCA, among other things, the Company and Vertex agreed to (a) allocate certain costs arising from a license agreement with a third party, resulting in a current payment due to Vertex by the Company of $20.0 million upon an event specified in Amendment No. 1 to the A&R Vertex JDCA, and (b) adjust, under certain specified circumstances, the timing of and portion of the Company’s share of costs it is permitted to defer under the agreement.

Letter Agreement

In May 2024, Vertex and the Company entered into a letter agreement, or the Letter Agreement, with respect to the priority review voucher issued by the U.S. Food and Drug Administration to Vertex as the sponsor of the rare pediatric disease product application for CASGEVY. Vertex and the Company agreed that if Vertex utilizes or transfers the priority review voucher prior to the first calendar year in which the CASGEVY program generates a net profit, Vertex will pay the Company $43.0 million or an amount equal to 42% of the net proceeds from such transfer, as applicable. If the CASGEVY program begins generating calendar-year net profits prior to such utilization or transfer, Vertex will instead pay the Company up to $43.0 million set-off by deductions Vertex would otherwise be eligible to take against the CASGEVY program’s net profits due to the Company related to amounts deferred previously by the Company.

Collaboration in the field of diabetes

In 2021, the Company and ViaCyte, Inc., or ViaCyte, entered into a joint development and commercialization agreement, as amended and in effect, from time to time, or the ViaCyte JDCA, to jointly develop and commercialize product candidates and shared products for the diagnosis, treatment or prevention of diabetes type 1, diabetes type 2 or insulin dependent / requiring diabetes throughout the world. In the third quarter of 2022, Vertex acquired ViaCyte, and ViaCyte became a wholly-owned subsidiary of Vertex. In March 2023, (1) the Company and ViaCyte entered into an amendment to the ViaCyte JDCA, or the ViaCyte JDCA Amendment, and adjusted certain rights and obligations of the Company and ViaCyte under the ViaCyte JDCA, and (2) the Company and Vertex entered into a non-exclusive license agreement, or the Non-Ex License Agreement, pursuant to which the Company agreed to license to Vertex, on a non-exclusive basis, certain of its gene editing intellectual property to exploit certain products for the diagnosis, treatment or prevention of diabetes type 1, diabetes type 2 or insulin dependent / requiring diabetes throughout the world. Subsequently, ViaCyte elected to opt-out of the ViaCyte JDCA. Per the opt-out terms, the on-going collaboration assets are now wholly owned by the Company, subject to a royalty on future sales owed to ViaCyte. The opt-out became effective in early February 2024.

Accounting Analysis

For purposes of this Note 6, the 2015 Collaboration Agreement, Amendment No. 1, Amendment No. 2, A&R Vertex JDCA, and Amendment No. 1 to the A&R Vertex JDCA are collectively referred to as the “Vertex Hemoglobinopathy Agreements” and the Non-Ex License Agreement and ViaCyte JDCA Amendment are collectively referred to as the “March 2023 Diabetes Agreements.”

The Vertex Hemoglobinopathy Agreements and the March 2023 Diabetes Agreements include components of a customer-vendor relationship as defined under ASC 606, Revenue from Contracts with Customers, or ASC 606, collaborative arrangements as defined under ASC 808, Collaborative Agreements, or ASC 808, and research and development costs as defined under ASC 730, Research and Development, or ASC 730. Specifically, with regards to the March 2023 Diabetes Agreements, the Company concluded that the non-exclusive license is a performance obligation under ASC 606 and the ongoing research and development services under the ViaCyte JDCA Amendment are a unit of account under ASC 808.

The Company has determined that recognition criteria for the Letter Agreement has not been met and will not be met until the priority review voucher is (i) utilized or (ii) there is sufficient profitability such that Vertex is obligated to pay the Company under the Letter Agreement.

Accounting Analysis Under ASC 606

Accounting for the Vertex Hemoglobinopathy Agreements

Recognition of Revenue

No revenue was recognized under the Vertex Hemoglobinopathy Agreements for the three and six months ended June 30, 2026 and 2025.

Milestones under the Vertex Hemoglobinopathy Agreements

The Company has evaluated the milestones that may be received in connection with the Vertex Hemoglobinopathy Agreements.

Under the 2015 Collaboration Agreement and subsequent amendments, the Company is eligible to receive up to $410.0 million in additional development, regulatory and commercial milestones and royalties on net product sales for each of the three collaboration targets that Vertex licensed in 2019. Each milestone is payable only once per collaboration target, regardless of the number of products directed to such collaboration target that achieve the relevant milestone event.

The Company has the option to conduct research at its own cost in certain defined areas. If such research is beneficial to the CASGEVY program and CASGEVY ultimately achieves regulatory approval in such areas, the Company could be entitled to receive from Vertex certain milestone payments aggregating to high eight digits.

Each of the remaining milestones described above are fully constrained as of June 30, 2026. There is uncertainty as to whether the events to obtain the research and developmental milestones will be achieved given the nature of clinical development and the stage of the CRISPR/Cas9 technology. The remaining research, development and regulatory milestones will be constrained until it is probable that a significant revenue reversal will not occur. Commercial milestones and royalties relate predominantly to a license of intellectual property and are determined by sales or usage-based thresholds. The commercial milestones and royalties are accounted for under the royalty recognition constraint and will be accounted for as constrained variable consideration. The Company applies the royalty recognition constraint for each commercial milestone and will not recognize revenue for each until the subsequent sale of a licensed product (achievement of each) occurs.

Accounting Analysis under ASC 808

Vertex Hemoglobinopathy Agreements

In connection with the Vertex Hemoglobinopathy Agreements, the Company identified the following collaborative elements, which are accounted for under ASC 808: (i) development and commercialization services for shared products, including any transition services related to CASGEVY under the A&R Vertex JDCA; (ii) R&D Services for follow-on products; and (iii) committee participation. The related impact of the cost sharing under the Vertex Hemoglobinopathy Agreements is included within collaboration expense, net, in the condensed consolidated statements of operations and comprehensive loss.

During the three and six months ended June 30, 2026, the Company recognized $40.3 million and $86.2 million, respectively, of collaboration expense, net, related to the Vertex Hemoglobinopathy Agreements. Collaboration expense, net, during the three and six months ended June 30, 2026 was net of $3.0 million and $4.2 million, respectively, of reimbursements from Vertex. During the three and six months ended June 30, 2025, the Company recognized $45.2 million and $102.7 million of collaboration expense, net, respectively. Collaboration expense, net, during the three and six months ended June 30, 2025 was net of $0.6 million and $0.7 million of reimbursements from Vertex, respectively.

Additional Accounting Considerations

The Company is eligible to receive potential future payments of up to $775.0 million upon the successful achievement of specified development, regulatory and commercial milestones under a strategic collaboration and license agreement from 2019 for the development and commercialization of products for the treatment of DMD and DM1. The Company is also eligible to receive tiered royalties on future net sales on any products that may result from this collaboration; however, the Company has the option to forego the DM1 milestones and royalties to co-develop and co-commercialize all DM1 products globally.

Each of the remaining milestones under the strategic collaboration and license agreement from 2019 for the development and commercialization of products for the treatment of DMD and DM1 are fully constrained as of June 30, 2026. There is uncertainty that the events to obtain the research and developmental milestones will be achieved given the nature of clinical development and the stage of the CRISPR/Cas9 technology. The remaining research, development and regulatory milestones will be constrained until it is probable that a significant revenue reversal will not occur. Commercial milestones and royalties relate predominantly to a license of intellectual property and are determined by sales or usage-based thresholds. The commercial milestones and royalties are accounted for under the royalty recognition constraint and will be accounted for as constrained variable consideration. The Company applies the royalty recognition constraint for each commercial milestone and will not recognize revenue for each until the subsequent sale of a licensed product (achievement of each) occurs.

As of June 30, 2026, there was $12.3 million of current deferred revenue, which is unchanged from December 31, 2025. The transaction price allocated to the remaining performance obligations was $12.3 million. Subsequent to June 30, 2026, the Company was notified by Vertex that it will not exercise an option granted under an amendment to the 2015 Collaboration Agreement to co-develop and co-commercialize a specified target and, as a result, the Company expects to recognize the related deferred revenue in the third quarter of 2026.

As of June 30, 2026, the Company is eligible to receive potential future milestone payments from Vertex of up to $125.0 million in the aggregate under the Non-Ex License Agreement depending on the achievement of pre-determined research, development and commercial milestones for certain products utilizing the licensed intellectual property. Additionally, the Company is eligible to receive tiered royalties on the sales of certain products in the low to mid-single digits.

Each of the remaining milestones under the Non-Ex License Agreement are fully constrained as of June 30, 2026. There is uncertainty as to whether the events to obtain the research and developmental milestones will be achieved given the nature of clinical development and the stage of the CRISPR/Cas9 technology. The remaining research, development and regulatory milestones will be constrained until it is probable that a significant revenue reversal will not occur. Commercial milestones and royalties relate predominantly to a license of intellectual property and are determined by sales or usage-based thresholds. The commercial milestones and royalties are accounted for under the royalty recognition constraint and will be accounted for as constrained variable consideration. The Company applies the royalty recognition constraint for each commercial milestone and will not recognize revenue for each until the subsequent sale of a licensed product (achievement of each) occurs.

Agreement with Sirius Therapeutics

In May 2025, the Company entered into a collaboration, option and license agreement, or the Sirius Agreement, with Sirius Therapeutics and certain of its affiliates, or Sirius, pursuant to which, among other things, (1) Sirius and the Company will collaborate on the research, development, manufacture, commercialization and use of certain collaboration products utilizing Sirius’ siRNA technology for targeting Factor XI, including CTX611, collectively, the Sirius Collaboration Products; and (2) Sirius granted to the Company options to exclusively license Sirius siRNA technology to target up to two licensed targets from a list of seven reserved targets for the research, development, manufacture and commercialization of licensed products, collectively the siRNA Licensed Products, in exchange for the potential to receive certain option fees, milestone payments and royalties.

In connection with entering into the Sirius Agreement, the Company made an upfront cash payment to Sirius of $25.0 million and also entered into a share issuance agreement with Sirius, pursuant to which the Company registered and issued to Sirius 1,842,105 common shares, nominal value CHF 0.03 per share, or common shares, equal to approximately $70.0 million based on a price per common share equal to $38.00, or the Sirius Shares.

With respect to Sirius Collaboration Products, the Company and Sirius will share equally all development and commercialization costs. For the first Sirius Collaboration Product successfully developed, the Company will be the lead party responsible for Phase 3 global development and commercialization efforts in the United States and Sirius will be the lead party responsible for Phase 3 development (subject to the global development plan) and commercialization efforts in Greater China. The parties will determine the lead party responsible for commercialization in the rest of the world at a future date. The Company and Sirius will share equally net profits and net losses incurred under the Sirius Agreement with respect to all Sirius Collaboration Products, except in the event that a party opts out of the joint development and commercialization. The Company will pay Sirius certain specified future development and regulatory milestones of up to an aggregate of $87.5 million for the first Sirius Collaboration Products to achieve the applicable milestone events. At the Company’s sole election, such milestone payments may be paid in cash, common shares of the Company, or a combination thereof.

With respect to the siRNA Licensed Products, if the Company elects to exercise its option to a licensed target to research, develop, manufacture and commercialize siRNA Licensed Products, the Company will make a one-time $10.0 million payment per option exercise, each, a Sirius Option Payment, to Sirius. The Sirius Option Payment is payable up to two times. In addition, the Company will pay Sirius certain specified future development, regulatory and sales milestones of up to an aggregate of $300.0 million for the first siRNA Licensed Product relating to each licensed target to achieve the applicable milestone events, as well as tiered royalty payments in the mid-single digits to low double digits range on future sales of a commercialized siRNA Licensed Product. The royalty payments are subject to reduction under certain specified conditions set forth in the Sirius Agreement. In addition, at the Company’s sole election, such milestones may be paid in cash, common shares of the Company, or a combination thereof. The Company is solely responsible for all research, development, manufacturing and global commercialization activities and associated costs for the siRNA Licensed Products, as well as all associated costs related to Sirius activities set forth in any applicable research plan relating thereto.

Accounting for the Sirius Agreement

The Sirius Agreement includes components of collaborative arrangements as defined under ASC 808 and research and development costs as defined under ASC 730.

Specifically, development and commercialization costs for the Sirius Collaboration Products contain collaborative elements accounted for under ASC 808, and the related impact of cost sharing for the Sirius Collaboration Products under the Sirius Agreement is included within research and development expenses in the condensed consolidated statements of operations and comprehensive loss. Costs related to siRNA Licensed Products under the Sirius Agreement are included within research and development expenses in the consolidated statement of operations and comprehensive loss.

Research and development costs under the Sirius Agreement related to the Sirius Collaboration Products were $3.4 million and $5.0 million for the three and six months ended June 30, 2026, respectively, and were net of $0.5 million and $0.7 million in reimbursements from Sirius, respectively. Research and development costs under the Sirius Agreement related to the siRNA Licensed Products were not material for the three and six months ended June 30, 2026. All research and development costs under the Sirius Agreement were not material for the three and six months ended June 30, 2025.

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2026	Jul. 31, 2026
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2026
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q2
Title of 12(b) Security	Common Shares, nominal value CHF 0.03
Trading Symbol	CRSP
Security Exchange Name	NASDAQ
Entity Registrant Name	CRISPR THERAPEUTICS AG
Entity Central Index Key	0001674416
Entity Tax Identification Number	00-0000000
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		96,692,653
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-37923
Entity Address, Address Line One	Baarerstrasse 14
Entity Address, City or Town	Zug
Entity Address, Country	CH
Entity Address, Postal Zip Code	6300
City Area Code	41 (0)41
Local Phone Number	561 32 79
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	V8
Document Quarterly Report	true
Document Transition Report	false

Stock-based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 17,316	$ 17,607	$ 33,640	$ 37,819
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	7,840	7,805	15,694	17,537
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 9,476	$ 9,802	$ 17,946	$ 20,282

Share Capital

6 Months Ended

Jun. 30, 2026

Equity [Abstract]

Share Capital

9. Share Capital

All of the Company’s common shares are authorized under Swiss corporate law with a nominal value of 0.03 CHF per share. Though the nominal value of common shares is stated in Swiss francs, the Company continues to use U.S. dollars as its reporting currency for preparing the condensed consolidated financial statements.

As of June 30, 2026, the Company’s share capital consists of 98,599,444 registered common shares with a nominal value of CHF 0.03 per share, 9,366,947 registered common shares reserved for potential issuance of bonds or similar instruments and 17,686,403 registered common shares reserved for the Company’s employee equity incentive plans. In addition, the Board of Directors is authorized to conduct one or more increases of the share capital at any time until June 8, 2028, or the expiration of the capital band if earlier, up to an upper limit of CHF 3,521,838.51 by issuing a corresponding number of registered shares with a nominal value of CHF 0.03 each to be fully paid in. As of June 30, 2026, the number of shares that may be issued under the capital band is 18,795,173 registered common shares.

Common Share Issuances

At-the-Market Offerings (ATM)

The Company has entered into an Open Market Sale AgreementSM, or the Sales Agreement, with Jefferies LLC under which the Company, at its sole discretion, is able to offer and sell, from time to time at prevailing market prices, its common shares. The following are in connection with the Sales Agreement.

2021 ATM

In January 2021, the Company filed a prospectus supplement with the SEC to offer and sell, from time to time, common shares having aggregate gross proceeds of up to $600.0 million, or, together with the subsequent prospectus supplements filed in July 2021 and August 2024 relating to the common shares remaining under the original prospectus supplement, the 2021 ATM.

For the three and six months ended June 30, 2025, the Company issued and sold an aggregate of 0.2 million common shares under the 2021 ATM at an average price of $54.33 per share for aggregate proceeds of $8.7 million, which were net of equity issuance costs of $0.1 million, excluding stamp taxes of $0.1 million.

As of December 31, 2025, the Company had issued and sold an aggregate of 8.0 million common shares under the 2021 ATM at an average price of $74.77 per share for aggregate proceeds of $592.2 million, which were net of equity issuance costs of $7.8 million, excluding stamp taxes of $5.9 million. As of December 31, 2025, no common shares remained available under the 2021 ATM.

2025 ATM

In October 2025, the Company filed a new prospectus supplement with the SEC to offer and sell, from time to time, common shares having aggregate gross proceeds of up to $600.0 million, or the 2025 ATM.

No common shares were issued and sold under the 2025 ATM for the three and six months ended June 30, 2026. As of June 30, 2026, the Company has issued and sold an aggregate of 0.7 million common shares under the 2025 ATM at an average price of $60.81 per share for aggregate proceeds of $42.3 million, which were net of equity issuance costs of $0.5 million, excluding stamp taxes of $0.4 million. Common shares having aggregate gross proceeds up to $557.2 million remain available under the 2025 ATM.

Share Issuance Agreement with Sirius Therapeutics

As described in Note 6 of the notes to our unaudited condensed consolidated financial statements included in this Quarterly Report on Form 10-Q, the Company and Sirius entered into a share issuance agreement in 2025 and the Company registered and issued 1,842,105 of the Company’s common shares to Sirius at an issue price of $38.00 per share as partial consideration for entering into the Sirius Agreement.

- Definition

The entire disclosure for equity.

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+ Details

Stock-based Compensation - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2026 USD ($)
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense related to stock options	$ 65.1
Unrecognized compensation expense, remaining weighted-average period for recognition	2 years 6 months
Restricted Common Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, remaining weighted-average period for recognition	2 years 7 months 6 days
Total unrecognized compensation expense	$ 85.3

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Paragraph 2
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Reference 28: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 2
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Segment Information

6 Months Ended

Jun. 30, 2026

Segment Reporting [Abstract]

Segment Information

13. Segment Information

The Company operates as one operating segment, which is the business of discovering, developing and commercializing therapies. The determination of a single business segment is consistent with the consolidated financial information regularly provided to the Company’s chief operating decision maker, or CODM. The Company’s chief executive officer, as the CODM, uses consolidated, single-segment financial information for purposes of evaluating performance, making operating decisions, allocating resources and planning and forecasting for future periods.

The CODM assesses performance and decides how to allocate resources based on consolidated net loss. The measure is used to monitor budget versus actual results to evaluate the performance of the segment.

The measure of segment assets is reported on the condensed consolidated balance sheets as total consolidated assets. All material long-lived assets are located in the United States. Long-lived assets consist of property and equipment, net, and operating lease right-of-use assets.

The following table illustrates information about segment revenue, significant segment expenses and segment operating loss for the periods presented (in thousands):


	Three Months Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Revenue:
Collaboration revenue	$	10,000		$	—		$	11,000		$	—
Grant revenue		181			892			639			1,757
Less1:
Research and development expense2		53,708			59,232			110,737			119,565
Acquired in-process research and development3		2,473			96,253			2,473			96,253
General and administrative expense4		5,957			6,840			12,553			13,357
Collaboration expense, net - Vertex5		40,272			45,153			86,221			102,662
Collaboration expense, net - Sirius6		3,444			500			4,950			500
Stock-based compensation expense		17,316			17,607			33,640			37,819
Depreciation expense		4,280			4,631			8,582			9,349
Other segment items7		(26,115	)		(20,775	)		(33,432	)		(33,203	)
Segment net loss		(91,154	)		(208,549	)		(214,085	)		(344,545	)
Reconciliation of profit or loss:
Adjustments or reconciling items		—			—			—			—
Consolidated net loss		(91,154	)		(208,549	)		(214,085	)		(344,545	)

(1) The significant expense categories and amounts align with the segment-level information that is regularly provided to the CODM.

$7.8 million and $17.5 million of stock-based compensation expense, respectively, and $2.4 million and $4.8 million of depreciation expense, respectively.

(7) Other segment items include interest income (expense), net, the change in fair value of corporate equity securities and income tax expense.

The Company operates in the United States and Switzerland. Collaboration revenue is attributed to the CRISPR Therapeutics AG entity, which is domiciled in Switzerland.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (b)
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/exampleRef
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Reference 13: http://www.xbrl.org/2003/role/exampleRef
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Reference 14: http://www.xbrl.org/2003/role/exampleRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147482810/280-10-50-41

+ Details

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Accrued Liabilities, Current [Abstract]
Payroll and employee-related costs	$ 8,468	$ 12,966
Research costs	16,965	16,247
Collaboration costs	37,226	53,567
Licensing fees	898	874
Professional fees	3,870	3,749
Intellectual property costs	2,344	1,382
Other	507	622
Total	$ 70,278	$ 89,407

Debt - Additional Information (Detail)		6 Months Ended
Debt - Additional Information (Detail)	Mar. 16, 2026 USD ($)	Jun. 30, 2026 USD ($) d $ / shares shares	Dec. 31, 2025 USD ($)	Jun. 30, 2025
Debt Instrument [Line Items]
Notes issuance date	Mar. 16, 2026
Effective coupon rate		0.50%		0.00%
Long-term debt		$ 586,198,000	$ 0
Convertible Senior Notes Due 2031 [Member]
Debt Instrument [Line Items]
Principal amount	$ 600,000,000	600,000,000	0
Amount of initial purchasers' option to purchase	$ 50,000,000
Notes stated interest rate	1.125%
Increase in coupon rate	0.6058%
Effective coupon rate	1.7308%
Basis for effective coupon rate	Because of anticipated 35% withholding on interest payments on the Notes under Swiss tax law, the Company agreed to increase the coupon by 0.6058% to 1.7308% to effectively eliminate the impact of such anticipated withholding on any holders who are not eligible to receive a refund.
Long-term debt	$ 585,400,000
Principal amount of converted notes		$ 1,000
Notes conversion price \| $ / shares		$ 76.56
Ratio of conversion of debt instrument into common stock \| shares		13.0617
Percentage of stock price trigger		130.00%
Conversion date		Mar. 06, 2029
Threshold trading days \| d		20
Threshold consecutive trading days \| d		30
Optional redemption price percentage to principal amount		100.00%
Sinking fund payments		$ 0
Debt instrument repurchase percentage		100.00%
Interest payable		$ 3,000,000	$ 0
Debt issuance costs		$ 14,600,000
Maximum [Member] \| Convertible Senior Notes Due 2031 [Member]
Debt Instrument [Line Items]
Ratio of conversion of debt instrument into common stock \| shares		18.9393
Number of shares issued upon conversion of debt instrument \| shares		11,363,580

Stock-based Compensation

6 Months Ended

Jun. 30, 2026

Share-Based Payment Arrangement [Abstract]

Stock-based Compensation

10. Stock-based Compensation

During the three and six months ended June 30, 2026 and 2025, the Company recognized the following stock-based compensation expense (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Research and development	$	7,840	$	7,805	$	15,694	$	17,537
General and administrative		9,476		9,802		17,946		20,282
Total	$	17,316	$	17,607	$	33,640	$	37,819

Stock option activity

The following table summarizes stock option activity for the six months ended June 30, 2026:


	Shares			Weighted- average exercise price per share
Outstanding at December 31, 2025		6,747,835		$	56.82
Granted		875,531			47.58
Exercised		(326,058	)		44.29
Cancelled or forfeited		(436,099	)		66.24
Outstanding at June 30, 2026		6,861,209		$	55.64
Exercisable at June 30, 2026		4,694,440		$	57.66
Vested and expected to vest at June 30, 2026		6,861,209		$	55.64

As of June 30, 2026, total unrecognized compensation expense related to stock options was $65.1 million, which the Company expects to recognize over a remaining weighted-average period of 2.5 years.

Restricted stock activity

The following table summarizes restricted stock activity for the six months ended June 30, 2026:


	Shares			Weighted- Average Grant Date Fair Value
Unvested balance at December 31, 2025		1,965,567		$	52.16
Granted		689,956			48.28
Vested		(429,134	)		53.28
Cancelled or forfeited		(169,286	)		50.69
Unvested balance at June 30, 2026		2,057,103		$	50.69

As of June 30, 2026, total unrecognized compensation expense related to unvested restricted common shares was $85.3 million, which the Company expects to recognize over a remaining weighted-average vesting period of 2.6 years.

Net Loss Per Share Attributable to Common Shareholders (Tables)

6 Months Ended

Jun. 30, 2026

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities not Include in Computation of Net Loss per Share

The Company did not include the securities in the following table in the computation of the net loss per share calculations for the three and six months ended June 30, 2026 and 2025 because the effect would have been anti-dilutive during each period:


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Outstanding options		6,861,209		7,434,169		6,861,209		7,434,169
Unvested restricted common shares		2,057,103		2,279,778		2,057,103		2,279,778
ESPP		11,426		24,606		11,426		24,606
Assumed conversion of the Notes		7,837,020		—		7,837,020		—
Total		16,766,758		9,738,553		16,766,758		9,738,553

Marketable Securities

6 Months Ended

Jun. 30, 2026

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

2. Marketable Securities


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
June 30, 2026
Cash equivalents:
Money market funds	$	30,639	$	—	$	—		$	30,639
Total cash equivalents		30,639		—		—			30,639
Marketable securities:
Corporate debt securities		1,374,062		579		(3,367	)		1,371,274
Certificates and term deposits		322,376		—		—			322,376
Government-sponsored enterprise securities		302,462		4		(1,893	)		300,573
Commercial paper		68,390		—		(34	)		68,356
Total marketable debt securities		2,067,290		583		(5,294	)		2,062,579
Corporate equity securities		7,500		2,936		—			10,436
Total marketable securities		2,074,790		3,519		(5,294	)		2,073,015
Total cash equivalents and marketable securities	$	2,105,429	$	3,519	$	(5,294	)	$	2,103,654
December 31, 2025
Cash equivalents:
Money market funds	$	37,255	$	—	$	—		$	37,255
Commercial paper		14,896		—		(4	)		14,892
Total cash equivalents		52,151		—		(4	)		52,147
Marketable securities:
Corporate debt securities		1,152,319		3,827		(181	)		1,155,965
Certificates of deposit		101,100		—		—			101,100
Government-sponsored enterprise securities		304,259		1,054		(15	)		305,298
Commercial paper		49,432		28		—			49,460
Total marketable debt securities		1,607,110		4,909		(196	)		1,611,823
Corporate equity securities		7,500		8,946		—			16,446
Total marketable securities		1,614,610		13,855		(196	)		1,628,269
Total cash equivalents and marketable securities	$	1,666,761	$	13,855	$	(200	)	$	1,680,416

The following table summarizes the net unrealized gain (loss) recorded on marketable debt and equity securities during the three and six months ended June 30, 2026 and 2025 (in millions):


	Three Months Ended						For the Six Months Ended
	June 30,						June 30,
	2026			2025			2026			2025
Unrealized (loss) gain recorded on marketable debt securities		(2.7	)		(0.2	)		(9.4	)		2.1
Unrealized gain (loss) recorded on marketable equity securities		6.1			1.8			(6.0	)		(6.4	)

Unrealized gains and losses on the Company’s marketable debt securities are included in comprehensive loss in the condensed consolidated statements of operations and comprehensive loss. Unrealized gains and losses due to the change in fair value of the Company’s marketable equity securities are included in other income (expense), net, in the condensed consolidated statements of operations and comprehensive loss.

The following table summarizes the net unrealized gain (loss) position of the Company’s marketable debt and equity securities as of June 30, 2026 and December 31, 2025 (in millions):


	June 30, 2026			December 31, 2025
Unrealized (loss) gain position of marketable debt securities	$	(4.7	)	$	4.7
Unrealized gain position of marketable equity securities		2.9			8.9


	June 30, 2026		December 31, 2025
Debt securities in an unrealized loss position for 12 months or less	$	1,292.3	$	193.8
Debt securities in an unrealized loss position for more than 12 months		—		—
Total debt securities in an unrealized loss position	$	1,292.3	$	193.8

There were no marketable debt securities in an unrealized loss position for more than twelve months with maturities beyond one year as of June 30, 2026 and December 31, 2025.

The Company determined that there is no material credit risk associated with the above investments as of June 30, 2026. The Company has the intent and ability to hold such securities until recovery. As a result, the Company did not record any charges for credit-related impairments for its marketable securities for the three and six months ended June 30, 2026 and 2025. No available-for-sale debt securities held as of June 30, 2026 had remaining maturities greater than thirty months.

Equity Investments Without Readily Determinable Fair Value

The Company holds investments in privately-held companies in the form of equity securities without readily determinable fair values and in which the Company does not have a controlling interest or significant influence. These investments had a carrying value of $35.9 million and $22.6 million as of June 30, 2026 and December 31, 2025, respectively, and are classified within other non-current assets on the condensed consolidated balance sheets. There were no upward or downward adjustments for observable price changes or impairment charges recorded for the three and six months ended June 30, 2026 and 2025 related to these equity securities.

Net Loss Per Share Attributable to Common Shareholders - Schedule of Antidilutive Securities not Include in Computation of Net Loss per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities not include in computation of net loss per share	16,766,758	9,738,553	16,766,758	9,738,553
Outstanding Options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities not include in computation of net loss per share	6,861,209	7,434,169	6,861,209	7,434,169
Unvested Restricted Common Shares [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities not include in computation of net loss per share	2,057,103	2,279,778	2,057,103	2,279,778
ESPP [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities not include in computation of net loss per share	11,426	24,606	11,426	24,606
Assumed Conversion of the Notes [Memeber]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities not include in computation of net loss per share	7,837,020	0	7,837,020	0

Segment Information - Additional Information (Details)	6 Months Ended
Segment Information - Additional Information (Details)	Jun. 30, 2026 Segment
Segment Reporting [Abstract]
Number of operating segments	1
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	srt:ChiefExecutiveOfficerMember
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	The CODM assesses performance and decides how to allocate resources based on consolidated net loss.

Segment Information - Schedule of Reportable Segment Profit and Loss, Including Significant Expense Categories, Attributable to the Company's Reportable Segment (Details) - USD ($)
$ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2026

Mar. 31, 2026

Jun. 30, 2025

Mar. 31, 2025

Jun. 30, 2026

Jun. 30, 2025

Revenues [Abstract]

Total revenue

$ 10,181

$ 892

$ 11,639

$ 1,757

Operating Expenses [Abstract]

Research and development

67,152

69,894

135,726

142,378

Acquired in-process research and development

2,473

96,253

2,473

96,253

General and administrative expense

17,553

18,916

34,736

38,212

Collaboration expense, net

40,272

45,153

86,221

102,662

Stock-based compensation expense

33,640

37,819

Depreciation expense

4,300

4,600

8,600

9,300

Segment net loss

(214,085)

(344,545)

Net loss

(91,154)

$ (122,931)

(208,549)

$ (135,996)

(214,085)

(344,545)

Sirius [Member]

Operating Expenses [Abstract]

Acquired in-process research and development

96,300

Collaboration Revenue [Member]

Revenues [Abstract]

Total revenue

10,000

11,000

Grant Revenue [Member]

Revenues [Abstract]

Total revenue

181

892

639

1,757

Operating Segments [Member]

Operating Expenses [Abstract]

Research and development

^[1],[2]

53,708

59,232

110,737

119,565

Acquired in-process research and development

^[1],[3]

2,473

96,253

2,473

96,253

General and administrative expense

^[1],[4]

5,957

6,840

12,553

13,357

Stock-based compensation expense

^[1]

17,316

17,607

33,640

37,819

Depreciation expense

^[1]

4,280

4,631

8,582

9,349

Other segment items

^[1],[5]

(26,115)

(20,775)

(33,432)

(33,203)

Segment net loss

(91,154)

(208,549)

(214,085)

(344,545)

Adjustments or reconciling items

Net loss

(91,154)

(208,549)

(214,085)

(344,545)

Operating Segments [Member] | Vertex [Member]

Operating Expenses [Abstract]

Collaboration expense, net

^[1],[6]

40,272

45,153

86,221

102,662

Operating Segments [Member] | Sirius [Member]

Operating Expenses [Abstract]

Collaboration expense, net

^[1],[7]

3,444

500

4,950

500

Operating Segments [Member] | Collaboration Revenue [Member]

Revenues [Abstract]

Total revenue

10,000

11,000

Operating Segments [Member] | Grant Revenue [Member]

Revenues [Abstract]

Total revenue

$ 181

$ 892

$ 639

$ 1,757

[1]	(1) The significant expense categories and amounts align with the segment-level information that is regularly provided to the CODM.
[2]	(2) Research and development expense for the three and six months ended June 30, 2026 excludes $7.8 million and $15.7 million of stock-based compensation expense, respectively, and $2.2 million and $4.4 million of depreciation expense, respectively. Research and development expense for the three and six months ended June 30, 2025 excludes $7.8 million and $17.5 million of stock-based compensation expense, respectively, and $2.4 million and $4.8 million of depreciation expense, respectively.
[3]	(3) Acquired in-process research and development expense for the three and six months ended June 30, 2026 was not material. The $96.3 million acquired in-process research and development expense for the three and six months ended June 30, 2025 is attributable to the costs incurred upon entering the Sirius Agreement, as described in Note 6 of the notes to our unaudited condensed consolidated financial statements included in this Quarterly Report on Form 10-Q.
[4]	(4) General and administrative expense for the three and six months ended June 30, 2026 excludes $9.5 million and $17.9 million of stock-based compensation expense, respectively, and $2.1 million and $4.2 million of depreciation expense, respectively. General and administrative expense for the three and six months ended June 30, 2025 excludes $9.8 million and $20.3 million of stock-based compensation expense, respectively, and $2.3 million and $4.6 million of depreciation expense, respectively.
[5]	(7) Other segment items include interest income (expense), net, the change in fair value of corporate equity securities and income tax expense.
[6]	(5) Collaboration costs specific to the Vertex Hemoglobinopathy Agreements (as defined in Note 6) accounted for under ASC 808 are presented within “collaboration expense, net” in the condensed consolidated statements of operations and comprehensive loss.
[7]	(6) In the second quarter of 2025, the Company entered into the Sirius Agreement (as defined in Note 6). Collaboration costs, net of reimbursements, related to the Sirius Collaboration Products under the Sirius Agreement are presented within “research and development expense” in the condensed consolidated statements of operations and comprehensive loss. In the first quarter of 2026, the significant expense categories reviewed by the CODM were updated to include collaboration costs, net of reimbursements, associated with the Sirius Collaboration Products. As a result, the Company recast segment amounts for the three and six months ended June 30, 2025 to reflect the updated significant expense categories.

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Current assets:
Cash and cash equivalents	$ 291,337	$ 347,559
Marketable securities	2,073,015	1,628,269
Prepaid expenses and other current assets	7,418	9,843
Total current assets	2,371,770	1,985,671
Property and equipment, net	108,068	115,851
Restricted cash	7,629	7,629
Operating lease assets	125,592	131,724
Other non-current assets	37,711	24,368
Total assets	2,650,770	2,265,243
Current liabilities:
Accounts payable	11,307	11,138
Accrued expenses	70,278	89,407
Deferred revenue, current	15,189	15,771
Accrued tax liabilities	494	1,113
Operating lease liabilities	18,646	18,578
Other current liabilities	16,982	13,113
Total current liabilities	132,896	149,120
Long-term debt	586,198	0
Operating lease liabilities, net of current portion	178,904	188,168
Other non-current liabilities	6,221	6,142
Total liabilities	904,219	343,430
Commitments and contingencies, see Note 7
Shareholders’ equity:
Common shares, CHF 0.03 nominal value, 144,447,967 and 132,477,166 shares authorized at June 30, 2026 and December 31, 2025, respectively, 96,761,275 and 96,009,657 shares issued at June 30, 2026 and December 31, 2025, respectively, 96,660,959 and 95,894,341 shares outstanding at June 30, 2026 and December 31, 2025, respectively	3,130	3,087
Treasury shares, at cost, 100,316 and 115,316 shares at June 30, 2026 and December 31, 2025, respectively.	(60)	(60)
Additional paid-in capital	3,909,746	3,861,516
Accumulated deficit	(2,161,636)	(1,947,551)
Accumulated other comprehensive (loss) income	(4,629)	4,821
Total shareholders' equity	1,746,551	1,921,813
Total liabilities and shareholders’ equity	$ 2,650,770	$ 2,265,243

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Revenue:
Total revenue	$ 10,181	$ 892	$ 11,639	$ 1,757
Operating expenses:
Research and development	67,152	69,894	135,726	142,378
Acquired in-process research and development	2,473	96,253	2,473	96,253
General and administrative	17,553	18,916	34,736	38,212
Collaboration expense, net	40,272	45,153	86,221	102,662
Total operating expenses	127,450	230,216	259,156	379,505
Loss from operations	(117,269)	(229,324)	(247,517)	(377,748)
Other income:
Other income, net	27,075	22,067	35,231	35,604
Total other income, net	27,075	22,067	35,231	35,604
Net loss before income taxes	(90,194)	(207,257)	(212,286)	(342,144)
Provision for income taxes	(960)	(1,292)	(1,799)	(2,401)
Net loss	(91,154)	(208,549)	(214,085)	(344,545)
Foreign currency translation adjustment	6	80	(26)	121
Unrealized (loss) gain on marketable securities	(2,694)	(174)	(9,424)	2,080
Comprehensive loss	$ (93,842)	$ (208,643)	$ (223,535)	$ (342,344)
Net loss per common share - basic	$ (0.94)	$ (2.4)	$ (2.22)	$ (3.98)
Basic weighted-average common shares outstanding	96,514,102	87,069,690	96,283,944	86,507,330
Net loss per common share - diluted	$ (0.94)	$ (2.4)	$ (2.22)	$ (3.98)
Diluted weighted-average common shares outstanding	96,514,102	87,069,690	96,283,944	86,507,330
Collaboration Revenue [Member]
Revenue:
Total revenue	$ 10,000	$ 0	$ 11,000	$ 0
Grant Revenue [Member]
Revenue:
Total revenue	$ 181	$ 892	$ 639	$ 1,757

Accrued Expenses

6 Months Ended

Jun. 30, 2026

Payables and Accruals [Abstract]

Accrued Expenses

5. Accrued Expenses

Accrued expenses consist of the following (in thousands):


	As of
	June 30,		December 31,
	2026		2025
Payroll and employee-related costs	$	8,468	$	12,966
Research costs		16,965		16,247
Collaboration costs		37,226		53,567
Licensing fees		898		874
Professional fees		3,870		3,749
Intellectual property costs		2,344		1,382
Other		507		622
Total	$	70,278	$	89,407

Fair Value Measurements

6 Months Ended

Jun. 30, 2026

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the fair value hierarchy classification of such fair values as of June 30, 2026 and December 31, 2025 (in thousands):


	Fair Value Measurements at
	June 30, 2026
	Total		Level 1		Level 2		Level 3
Cash and cash equivalents:
Cash	$	260,698	$	260,698	$	—	$	—
Money market funds		30,639		30,639		—		—
Marketable securities:
Corporate debt securities		1,371,274		—		1,371,274		—
Certificates and term deposits		322,376		—		322,376		—
Government-sponsored enterprise securities		300,573		—		300,573		—
Commercial paper		68,356		—		68,356		—
Corporate equity securities		10,436		4,144		6,292		—
Total	$	2,364,352	$	295,481	$	2,068,871	$	—

	Fair Value Measurements at
	December 31, 2025
	Total		Level 1		Level 2		Level 3
Cash and cash equivalents:
Cash	$	295,412	$	295,412	$	—	$	—
Money market funds		37,255		37,255		—		—
Commercial paper		14,892		—		14,892		—
Marketable securities:
Corporate debt securities		1,155,965		—		1,155,965		—
Certificates of deposit		101,100		—		101,100		—
Government-sponsored enterprise securities		305,298		—		305,298		—
Commercial paper		49,460		—		49,460		—
Corporate equity securities		16,446		—		16,446		—
Total	$	1,975,828	$	332,667	$	1,643,161	$	—

Marketable securities classified as Level 1 within the valuation hierarchy consist of corporate equity securities with quoted prices in active markets. Marketable securities classified as Level 2 within the valuation hierarchy generally consist of U.S. treasury securities and government agency securities, certificates of deposit, corporate bonds, commercial paper and warrants to purchase common shares of publicly traded companies. The Company estimates the fair value of these marketable securities by taking into consideration valuations obtained from third-party pricing sources.

Notes

The fair value of the Company’s Convertible Senior Notes due 2031, or the Notes, which differs from their respective carrying values, is determined by prices for the Notes observed in market trading and classified as Level 2 within the valuation hierarchy. The Notes are described in further detail in Note 8 of the notes to the condensed consolidated financial statements included in this Quarterly Report on Form 10-Q.

The following table presents the aggregate face values and the fair values of the Notes, based on their market prices on the last trading day for the periods presented (in thousands):


	June 30, 2026				December 31, 2025
	Aggregate Face Values		Estimated Fair Values		Aggregate Face Values		Estimated Fair Values
Notes	$	600,000	$	636,360	$	—	$	—

- Definition

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

+ References

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+ Details

Income Taxes

6 Months Ended

Jun. 30, 2026

Income Tax Disclosure [Abstract]

Income Taxes

12. Income Taxes

During the three and six months ended June 30, 2026, the Company recorded an income tax provision of $1.0 million and $1.8 million, respectively, representing an effective tax rate of (1.1%) and (0.9%), respectively. During the three and six months ended June 30, 2025, the Company recorded an income tax provision of $1.3 million and $2.4 million, respectively, representing an effective tax rate of (0.6%) and (0.7%), respectively. The income tax provision for the three and six months ended June 30, 2026 is primarily attributable to the income generated by the Company’s U.S. subsidiaries. The difference in the statutory tax rate and effective tax rate is primarily a result of the jurisdictional mix of earnings, research credits generated, and the valuation allowance recorded against certain deferred tax assets. The Company maintains a valuation allowance against certain deferred tax assets that are not more-likely-than-not realizable.

- Definition

The entire disclosure for income tax.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	$ 2,062,579	$ 1,611,823
Recurring Basis [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	2,364,352	1,975,828
Recurring Basis [Member] \| Cash [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	260,698	295,412
Recurring Basis [Member] \| Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	30,639	37,255
Recurring Basis [Member] \| Commercial Paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents		14,892
Marketable securities, fair value	68,356	49,460
Recurring Basis [Member] \| Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	1,371,274	1,155,965
Recurring Basis [Member] \| Certificates and Term Deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	322,376
Recurring Basis [Member] \| Certificates of Deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value		101,100
Recurring Basis [Member] \| Government-sponsored Enterprise Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	300,573	305,298
Recurring Basis [Member] \| Corporate Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	10,436	16,446
Recurring Basis [Member] \| Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	295,481	332,667
Recurring Basis [Member] \| Level 1 [Member] \| Cash [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	260,698	295,412
Recurring Basis [Member] \| Level 1 [Member] \| Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	30,639	37,255
Recurring Basis [Member] \| Level 1 [Member] \| Corporate Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	4,144
Recurring Basis [Member] \| Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	2,068,871	1,643,161
Recurring Basis [Member] \| Level 2 [Member] \| Commercial Paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents		14,892
Marketable securities, fair value	68,356	49,460
Recurring Basis [Member] \| Level 2 [Member] \| Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	1,371,274	1,155,965
Recurring Basis [Member] \| Level 2 [Member] \| Certificates and Term Deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	322,376
Recurring Basis [Member] \| Level 2 [Member] \| Certificates of Deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value		101,100
Recurring Basis [Member] \| Level 2 [Member] \| Government-sponsored Enterprise Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	300,573	305,298
Recurring Basis [Member] \| Level 2 [Member] \| Corporate Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fair value	$ 6,292	16,446
Recurring Basis [Member] \| Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total		$ 0

Marketable Securities - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]
Marketable securities	$ 260.7	$ 295.4
Marketable securities, non-current	0.0	0.0
Available-for-sale debt securities remaining maturities greater than thirty months	0.0
Equity investments without readily determinable fair value	$ 35.9	$ 22.6

Basis of Presentation and Significant Accounting Policies

6 Months Ended

Jun. 30, 2026

Accounting Policies [Abstract]

Basis of Presentation and Significant Accounting Policies

1. Basis of Presentation and Significant Accounting Policies

Basis of Presentation

The accompanying condensed consolidated financial statements are unaudited and have been prepared by the Company in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP.

The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company views its operations and manages its business in one operating segment, which is the business of discovering, developing and commercializing therapies. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These interim financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the financial position and results of operations for the three and six-month interim periods ended June 30, 2026 and 2025.

Certain prior period amounts have been reclassified to conform to the current presentation. Specifically, the Company reclassified “Sales of marketable securities” in the condensed consolidated statements of cash flows, which were classified within “Maturities of marketable securities” in prior periods. As a result, no subtotals in the prior year condensed consolidated financial statements were impacted.

The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These interim financial statements should be read in conjunction with the audited financial statements for the year ended December 31, 2025, which are contained in the 2025 Annual Report on Form 10-K filed with the Securities and Exchange Commission, or the SEC, on February 12, 2026.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates, which include, but are not limited to, revenue recognition, equity-based compensation expense and reported amounts of expenses during the period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions. Changes in estimates are reflected in reported results in the period in which they become known.

Significant Accounting Policies

The significant accounting policies used in preparation of these condensed consolidated financial statements for the three and six months ended June 30, 2026 are consistent with those discussed in Note 2 to the consolidated financial statements in the Company’s 2025 Annual Report on Form 10-K filed with the SEC on February 12, 2026, with the exception of the new policy below. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Updates, or ASUs, of the Financial Accounting Standards Board, or FASB.

Convertible Debt

The Company accounts for its convertible debt instruments as a single unit of accounting, a liability, as the Company concluded that the conversion features do not require bifurcation as a derivative under ASC Topic 815-15, Derivatives and Hedging, as the Company did not issue its convertible debt instruments at a substantial premium. The Company records debt issuance costs as contra-liabilities in its condensed consolidated balance sheets at issuance and amortizes debt issuance costs over the contractual term of the convertible debt instrument using the effective interest rate. The balance of the Company’s Notes (as defined below) presented in its condensed consolidated balance sheets represents the principal balance of the convertible debt instrument less unamortized debt issuance costs. Please refer to Note 8 of the notes to the condensed consolidated financial statements included in this Quarterly Report on Form 10-Q for further information.

Recent Accounting Pronouncements

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures, and in January 2025, the FASB issued ASU 2025-01, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures: Clarifying the Effective Date. ASU 2024-03 requires disclosure of additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. ASU 2024-03, as clarified by ASU 2025-01, is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after

December 15, 2027, with early adoption permitted. The Company is currently evaluating the disclosure requirements related to this new standard.

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025
Operating activities:
Net loss	$ (214,085)	$ (344,545)
Reconciliation of net loss to net cash used in operating activities:
Depreciation and amortization	8,599	9,385
Equity-based compensation	33,640	37,819
Other non-cash items, net	(4,763)	(5,075)
Amortization of debt issuance costs	848	0
Acquired in-process research and development	2,473	96,253
Changes in:
Accounts receivable	0	25,000
Prepaid expenses and other assets	(1,088)	(727)
Accounts payable and accrued expenses	(18,321)	28,298
Deferred revenue	(582)	(1,716)
Operating lease assets and liabilities	(3,064)	(2,421)
Other liabilities, net	3,948	(10,098)
Net cash used in operating activities	(192,395)	(167,827)
Investing activities:
Purchases of property, plant and equipment	(1,152)	(323)
Investment in equity securities	(13,343)	(9,700)
Purchases of in-process research and development	(2,473)	(25,000)
Purchases of marketable securities	(952,388)	(411,111)
Maturities of marketable securities	184,253	397,147
Sales of marketable securities	318,701	99,209
Net cash (used in) provided by investing activities	(466,402)	50,222
Financing activities:
Proceeds from issuance of the Notes	600,000	0
Issuance costs and discounts associated with the Notes	(14,650)	0
(Payments) proceeds from issuance of common shares, net of issuance costs	(722)	8,494
Proceeds from exercise of options and ESPP contributions, net of issuance costs	14,460	4,352
Net cash provided by financing activities	599,088	12,846
Effect of exchange rate changes on cash	(26)	121
Decrease in cash	(59,735)	(104,638)
Cash, cash equivalents and restricted cash, beginning of period	359,078	309,776
Cash, cash equivalents and restricted cash, end of period	299,343	205,138
Supplemental disclosure of non-cash investing and financing activities
Equity issuance costs in accounts payable, accrued expenses, and other long-term liabilities	3,935	3,899
Acquired in-process research and development expense related to issuance of common shares	$ 0	$ 71,253

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2026	Mar. 31, 2026	Jun. 30, 2025	Mar. 31, 2025
Common Shares [Member]
Issuance costs			$ 0.7	$ 0.1
Employee Stock Option
Issuance costs	$ 0.2	$ 0.2	$ 0.1	$ 0.2

Condensed Consolidated Balance Sheets (Parenthetical) - SFr / shares	Jun. 30, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Common stock, par value	SFr 0.03	SFr 0.03
Common stock, shares authorized	144,447,967	132,477,166
Common stock, shares issued	96,761,275	96,009,657
Common stock, shares outstanding	96,660,959	95,894,341
Treasury stock, shares	100,316	115,316

Accrued Expenses (Tables)

6 Months Ended

Jun. 30, 2026

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consist of the following (in thousands):


	As of
	June 30,		December 31,
	2026		2025
Payroll and employee-related costs	$	8,468	$	12,966
Research costs		16,965		16,247
Collaboration costs		37,226		53,567
Licensing fees		898		874
Professional fees		3,870		3,749
Intellectual property costs		2,344		1,382
Other		507		622
Total	$	70,278	$	89,407

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2026

Fair Value Disclosures [Abstract]

Schedule of Financial Assets Measured at Fair Value on Recurring Basis


	Fair Value Measurements at
	June 30, 2026
	Total		Level 1		Level 2		Level 3
Cash and cash equivalents:
Cash	$	260,698	$	260,698	$	—	$	—
Money market funds		30,639		30,639		—		—
Marketable securities:
Corporate debt securities		1,371,274		—		1,371,274		—
Certificates and term deposits		322,376		—		322,376		—
Government-sponsored enterprise securities		300,573		—		300,573		—
Commercial paper		68,356		—		68,356		—
Corporate equity securities		10,436		4,144		6,292		—
Total	$	2,364,352	$	295,481	$	2,068,871	$	—

	Fair Value Measurements at
	December 31, 2025
	Total		Level 1		Level 2		Level 3
Cash and cash equivalents:
Cash	$	295,412	$	295,412	$	—	$	—
Money market funds		37,255		37,255		—		—
Commercial paper		14,892		—		14,892		—
Marketable securities:
Corporate debt securities		1,155,965		—		1,155,965		—
Certificates of deposit		101,100		—		101,100		—
Government-sponsored enterprise securities		305,298		—		305,298		—
Commercial paper		49,460		—		49,460		—
Corporate equity securities		16,446		—		16,446		—
Total	$	1,975,828	$	332,667	$	1,643,161	$	—

Aggregate Face Values and the Fair values of the Notes

The following table presents the aggregate face values and the fair values of the Notes, based on their market prices on the last trading day for the periods presented (in thousands):


	June 30, 2026				December 31, 2025
	Aggregate Face Values		Estimated Fair Values		Aggregate Face Values		Estimated Fair Values
Notes	$	600,000	$	636,360	$	—	$	—

Debt

6 Months Ended

Jun. 30, 2026

Debt Disclosure [Abstract]

Debt

8. Debt

Notes, net

In March 2026, the Company issued $600.0 million aggregate principal amount of the Notes, pursuant to an indenture dated March 16, 2026, or the Indenture, between the Company and U.S. Bank Trust Company, National Association, as trustee, in a private offering to qualified institutional buyers, or the 2026 Note Offering. The Notes issued in the 2026 Note Offering include the exercise in full of the initial purchasers’ option to purchase $50.0 million of additional Notes. The investors in the Notes agreed to an effective coupon of 1.125%. Because of anticipated 35% withholding on interest payments on the Notes under Swiss tax law, the Company agreed to increase the coupon by 0.6058% to 1.7308% to effectively eliminate the impact of such anticipated withholding on any holders who are not eligible to receive a refund.

The Notes are senior, unsecured obligations of the Company and will mature on March 1, 2031, or the maturity date, unless earlier converted, redeemed or repurchased. The Notes will accrue interest payable semiannually in arrears on March 1 and September 1 of each year, beginning on September 1, 2026. Holders may convert all or any portion of their Notes at their option prior to the maturity date, other than during a “conversion freeze period” (as defined in the Indenture). Upon conversion, the Company will deliver common shares at an initial conversion rate of 13.0617 common shares per $1,000 principal amount of Notes (equivalent to an initial conversion price of approximately $76.56 per common share), subject to adjustment in some events in accordance with the terms of the Indenture but will not be adjusted for any accrued and unpaid interest.

In addition, if certain corporate events occur or are anticipated to occur prior to the maturity date or if the Company delivers a notice of optional redemption, the Company will, in certain circumstances, increase the conversion rate for a holder who elects to convert its Notes in connection with such a corporate event or called (or deemed called) for redemption in connection with such notice of optional redemption. Initially, a maximum of 11,363,580 common shares may be delivered upon conversion of the Notes, based on the initial maximum conversion rate of 18.9393 common shares per $1,000 principal amount of Notes, which is subject to customary conversion rate adjustment provisions.

The Company may not redeem the Notes prior to March 6, 2029. On or after such date, the Company may redeem for cash all or any portion of the Notes (subject to the partial redemption limitation described in the Indenture), at its option, if the last reported sale price of its common shares has been at least 130% of the conversion price for the Notes then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides notice of optional redemption, at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the optional redemption date. No sinking fund is provided for the Notes.

If the Company undergoes a fundamental change (as defined in the Indenture), then, subject to certain conditions and except as described in the Indenture, holders may require the Company to repurchase for cash all or any portion of their Notes at a fundamental change repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

The Indenture includes customary covenants and sets forth certain events of default after which the Notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving the Company after which the Notes become automatically due and payable.

The Company received net proceeds from the 2026 Note Offering of approximately $585.4 million, after deducting the initial purchasers’ discounts and commissions and the estimated offering expenses payable by the Company. Additionally, in connection with the issuance of the Notes, the Company incurred approximately $14.6 million of debt issuance costs, which consisted of initial purchasers’ discounts, legal and professional fees. This was recorded as a reduction in the carrying value of the debt on the condensed consolidated balance sheets and is amortized to interest expense using the effective interest method over the expected life of the Notes, which is approximately five years.

Additional Information Related to the Notes

The outstanding balances of the Notes consisted of the following (in thousands):


	June 30, 2026			December 31, 2025
Principal	$	600,000		$	—
Unamortized debt discount and issuance costs		(13,802	)		—
Net carrying amount	$	586,198		$	—

The following table sets forth the total interest expense recognized and effective interest rates related to the Notes for the periods presented (in thousands):


	Three Months Ended June 30					Six Months Ended June 30
	2026			2025		2026			2025
Contractual interest expense	$	2,596		$	—	$	3,029		$	—
Amortization of debt discount and issuance costs		728			—		848			—
Total interest and amortization expense	$	3,324		$	—	$	3,877		$	—
Effective interest rate		0.5	%		—		0.5	%		—

As of June 30, 2026, interest payable on the Notes was $3.0 million. There was no interest payable on the Notes as of December 31, 2025. Such amounts are included in “Other current liabilities” in our condensed consolidated balance sheets.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-8A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 405
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477092/405-40-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 405
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477092/405-40-50-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 405
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477092/405-40-50-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 405
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477092/405-40-50-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 405
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477092/405-40-50-1

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org/470/tableOfContent

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1C

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1C

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1C

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1I

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1I

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1I

+ Details

Property and Equipment, net (Tables)

6 Months Ended

Jun. 30, 2026

Property, Plant and Equipment [Abstract]

Summary of Property and Equipment, Net

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


	As of
	June 30,			December 31,
	2026			2025
Computer equipment	$	4,152		$	4,152
Furniture, fixtures and other		8,554			8,554
Laboratory equipment		44,950			43,575
Leasehold improvements		146,788			146,667
Construction work in process		3,217			3,955
Total property and equipment, gross		207,661			206,903
Accumulated depreciation		(99,593	)		(91,052	)
Total property and equipment, net	$	108,068		$	115,851

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Shares [Member]	Treasury Shares [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income/(Loss)
Beginning balance at Dec. 31, 2024	$ 1,932,080	$ 2,698	$ (62)	$ 3,293,556	$ (1,365,952)	$ 1,840
Beginning balance, Shares at Dec. 31, 2024		85,741,981
Treasury stock, Beginning balance (in shares) at Dec. 31, 2024			170,316
Issuance of common shares, net of issuance costs	8,637	$ 5		8,632
Issuance of common shares, net of issuance costs (in shares)		162,482
Vesting of restricted shares	15	$ 15
Vesting of restricted shares (in shares)		396,943
Exercise of vested options, net of issuance costs	1,264	$ 3		1,261
Exercise of vested options, net of issuance costs (in shares)		39,996
Purchase of common stock under ESPP	653			653
Purchase of common stock under ESPP (in shares)		19,522
Stock-based compensation expense	20,212			20,212
Other comprehensive gain (loss)	2,295					2,295
Net Income (Loss)	(135,996)				(135,996)
Ending balance at Mar. 31, 2025	1,829,160	$ 2,721	$ (62)	3,324,314	(1,501,948)	4,135
Treasury Stock, Ending balance (in shares) at Mar. 31, 2025			170,316
Ending balance, Shares at Mar. 31, 2025		86,360,924
Beginning balance at Dec. 31, 2024	1,932,080	$ 2,698	$ (62)	3,293,556	(1,365,952)	1,840
Beginning balance, Shares at Dec. 31, 2024		85,741,981
Treasury stock, Beginning balance (in shares) at Dec. 31, 2024			170,316
Net Income (Loss)	(344,545)
Ending balance at Jun. 30, 2025	1,711,125	$ 2,794	$ (62)	3,414,849	(1,710,497)	4,041
Treasury Stock, Ending balance (in shares) at Jun. 30, 2025			170,316
Ending balance, Shares at Jun. 30, 2025		88,376,439
Beginning balance at Mar. 31, 2025	1,829,160	$ 2,721	$ (62)	3,324,314	(1,501,948)	4,135
Beginning balance, Shares at Mar. 31, 2025		86,360,924
Treasury stock, Beginning balance (in shares) at Mar. 31, 2025			170,316
Issuance of common shares, net of issuance costs	70,605	$ 65		70,540
Issuance of common shares, net of issuance costs (in shares)		1,842,105
Vesting of restricted shares	5	$ 5
Vesting of restricted shares (in shares)		104,941
Exercise of vested options, net of issuance costs	2,391	$ 3		2,388
Exercise of vested options, net of issuance costs (in shares)		68,469
Stock-based compensation expense	17,607			17,607
Other comprehensive gain (loss)	(94)					(94)
Net Income (Loss)	(208,549)				(208,549)
Ending balance at Jun. 30, 2025	1,711,125	$ 2,794	$ (62)	3,414,849	(1,710,497)	4,041
Treasury Stock, Ending balance (in shares) at Jun. 30, 2025			170,316
Ending balance, Shares at Jun. 30, 2025		88,376,439
Beginning balance at Dec. 31, 2025	$ 1,921,813	$ 3,087	$ (60)	3,861,516	(1,947,551)	4,821
Beginning balance, Shares at Dec. 31, 2025		95,894,341
Treasury stock, Beginning balance (in shares) at Dec. 31, 2025	115,316		115,316
Vesting of restricted shares	$ 22	$ 22
Vesting of restricted shares (in shares)		349,508
Exercise of vested options, net of issuance costs	5,619	$ 6		5,613
Exercise of vested options, net of issuance costs (in shares)		130,231
Purchase of common stock under ESPP	471			471
Purchase of common stock under ESPP (in shares)		11,426
Stock-based compensation expense	16,324			16,324
Other comprehensive gain (loss)	(6,762)					(6,762)
Net Income (Loss)	(122,931)				(122,931)
Ending balance at Mar. 31, 2026	1,814,556	$ 3,115	$ (60)	3,883,924	(2,070,482)	(1,941)
Treasury Stock, Ending balance (in shares) at Mar. 31, 2026			115,316
Ending balance, Shares at Mar. 31, 2026		96,385,506
Beginning balance at Dec. 31, 2025	$ 1,921,813	$ 3,087	$ (60)	3,861,516	(1,947,551)	4,821
Beginning balance, Shares at Dec. 31, 2025		95,894,341
Treasury stock, Beginning balance (in shares) at Dec. 31, 2025	115,316		115,316
Exercise of vested options, net of issuance costs (in shares)	326,058
Net Income (Loss)	$ (214,085)
Ending balance at Jun. 30, 2026	$ 1,746,551	$ 3,130	$ (60)	3,909,746	(2,161,636)	(4,629)
Treasury Stock, Ending balance (in shares) at Jun. 30, 2026	100,316		100,316
Ending balance, Shares at Jun. 30, 2026		96,660,959
Beginning balance at Mar. 31, 2026	$ 1,814,556	$ 3,115	$ (60)	3,883,924	(2,070,482)	(1,941)
Beginning balance, Shares at Mar. 31, 2026		96,385,506
Treasury stock, Beginning balance (in shares) at Mar. 31, 2026			115,316
Vesting of restricted shares	9	$ 9
Vesting of restricted shares (in shares)		79,626
Exercise of vested options, net of issuance costs	8,512	$ 6		8,506
Exercise of vested options, net of issuance costs (in shares)		195,827	(15,000)
Stock-based compensation expense	17,316			17,316
Other comprehensive gain (loss)	(2,688)					(2,688)
Net Income (Loss)	(91,154)				(91,154)
Ending balance at Jun. 30, 2026	$ 1,746,551	$ 3,130	$ (60)	$ 3,909,746	$ (2,161,636)	$ (4,629)
Treasury Stock, Ending balance (in shares) at Jun. 30, 2026	100,316		100,316
Ending balance, Shares at Jun. 30, 2026		96,660,959

Basis of Presentation and Significant Accounting Policies - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2026 Segment
Accounting Policies [Abstract]
Number of operating segments	1

Segment Information - Schedule of Reportable Segment Profit and Loss, Including Significant Expense Categories, Attributable to the Company's Reportable Segment (Parenthetical) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting Information [Line Items]
Stock-based compensation expense	$ 17,316	$ 17,607	$ 33,640	$ 37,819
Depreciation expense	4,300	4,600	8,600	9,300
Acquired in-process research and development	2,473	96,253	2,473	96,253
Sirius Agreement [Member]
Segment Reporting Information [Line Items]
Acquired in-process research and development		96,300		96,300
Research and Development Expense [Member]
Segment Reporting Information [Line Items]
Stock-based compensation expense	7,840	7,805	15,694	17,537
Depreciation expense	2,200	2,400	4,400	4,800
General and Administrative Expense [Member]
Segment Reporting Information [Line Items]
Stock-based compensation expense	9,476	9,802	17,946	20,282
Depreciation expense	$ 2,100	$ 2,300	$ 4,200	$ 4,600

Net Loss Per Share Attributable to Common Shareholders

6 Months Ended

Jun. 30, 2026

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Shareholders

11. Net Loss Per Share Attributable to Common Shareholders

Basic net loss per share is calculated by dividing net loss attributable to common shareholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per share is calculated by adjusting net loss to remove the effects from potential dilutive common shares and dividing this adjusted amount by the weighted average number of common shares and potential dilutive common shares outstanding for the period. For purposes of the diluted net loss per share calculation, stock options, unvested restricted common shares, ESPP shares and shares issuable under an assumed conversion of the Notes are considered to be common stock equivalents but are excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive; therefore, basic and diluted net loss per share were the same for all periods presented as a result of the Company’s net loss. The Company’s net loss is net loss attributable to common shareholders for all periods presented.


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Outstanding options		6,861,209		7,434,169		6,861,209		7,434,169
Unvested restricted common shares		2,057,103		2,279,778		2,057,103		2,279,778
ESPP		11,426		24,606		11,426		24,606
Assumed conversion of the Notes		7,837,020		—		7,837,020		—
Total		16,766,758		9,738,553		16,766,758		9,738,553