Number of share options (or share units) assumed during the period in connection with the merger.

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Weighted average price at which the grantees can acquire the shares of common stock for the stock options that were assumed in connection with the merger.

+ References

No definition available.

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The number of shares into which unvested stock options outstanding as of the balance sheet date can be early converted under the option plan.

+ References

No definition available.

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n/a

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No definition available.

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No definition available.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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Weighted average price of options that were either forfeited or expired.

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- Definition

Gross number of share options (or share units) granted during the period.

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
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-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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-Publisher FASB
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

+ References

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Subparagraph (e)(1)
-Name Accounting Standards Codification
-Paragraph 2
-Section 50
-Publisher FASB
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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Stock option plans excluding the 2024 POP
Options Outstanding
Options outstanding at beginning of the period (shares)	7,670,908
Stock options assumed in connection with the ACELYRIN Merger (shares)	4,712,186
Granted (shares)	6,983,120
Forfeited or expired (shares)	(956,679)
Options outstanding, vested and expected to vest at end of the period (shares)	18,409,535		7,670,908
Exercisable at end of the period (shares)	10,661,758
Weighted- Average Exercise Price Per Share
Weighted-average exercise price, Outstanding at beginning of the period ($ per shares)	$ 9.59
Weighted-average exercise price, Stock options assumed in connection with the ACELYRIN Merger ($ per shares)	12.99
Weighted-average exercise price, Granted ($ per shares)	4.6
Weighted-average exercise price, Forfeited or expired ($ per shares)	9.07
Weighted-average exercise price, Outstanding, vested and expected to vest at end of the period ($ per shares)	8.6		$ 9.59
Exercisable at end of the period ($ per shares)	$ 10.66
Weighted- Average Remaining Contractual Term
Weighted-average remaining contractual term, Outstanding, vested and expected to vest (in years)	7 years		8 years 2 months 12 days
Weighted-average remaining contractual term, Exercisable at end of the period (in years)	5 years 2 months 12 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding at beginning of the period	$ 1,777
Aggregate Intrinsic Values, Outstanding, vested and expected to vest at the end of period	388		$ 1,777
Aggregate Intrinsic Values, Exercisable at the end of period	116
Vested, fair value	$ 22,100	$ 5,400
2021 Plan
Aggregate Intrinsic Value
Unvested and early exercisable shares	2,304,921
2024 POP
Options Outstanding
Options outstanding at beginning of the period (shares)	1,787,880
Forfeited or expired (shares)	(107,056)
Options outstanding, vested and expected to vest at end of the period (shares)	1,680,824		1,787,880
Weighted- Average Exercise Price Per Share
Weighted-average exercise price, Outstanding at beginning of the period ($ per shares)	$ 10.19
Weighted-average exercise price, Forfeited or expired ($ per shares)	10.19
Weighted-average exercise price, Outstanding, vested and expected to vest at end of the period ($ per shares)	$ 10.19		$ 10.19
Weighted- Average Remaining Contractual Term
Weighted-average remaining contractual term, Outstanding, vested and expected to vest (in years)	8 years 7 months 6 days		9 years 3 months 18 days