The maximum amount of annual sales on which royalty payments are paid under the royalty purchase agreement.

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

The maximum amount of payments receivable for additional milestones under the royalty purchase agreement.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Maximum royalty payments under the royalty purchase agreement made before royalty interest reverts back to the Company.

+ References

No definition available.

+ Details

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Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow paid to third parties for transaction costs in connection with a monetization transaction of future SPINRAZA and pelacarsen royalties the Company is entitled to under collaboration and licensing agreements.

+ References

No definition available.

+ Details

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Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage of royalty payments paid on annual sales of medicine.

+ References

No definition available.

+ Details

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Namespace Prefix:	ions_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of upfront payments received during the period under the royalty purchase agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479402/808-10-50-1

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Period Type:	duration

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

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-Topic 210
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-Topic 470
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- Details

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- Details

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- Details

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- Details

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Liability Related to Sale of Future Royalties (Details) - Royalty Purchase Agreement [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Jun. 30, 2025	Jun. 30, 2024
Royalty Revenue Monetization [Abstract]
Upfront payment received	$ 500.0
Maximum amount of payments receivable for additional milestones		$ 625.0
Transaction costs	$ 10.4
Effective interest rate		12.70%	13.50%
SPINRAZA [Member]
Royalty Revenue Monetization [Abstract]
Maximum amount of annual sales on which royalty payments are paid		$ 1,500.0
SPINRAZA [Member] \| Minimum [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine		25.00%
Maximum royalty payments made before royalty interest reverts back		$ 475.0
SPINRAZA [Member] \| Maximum [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine		45.00%
Maximum royalty payments made before royalty interest reverts back		$ 550.0
Pelacarsen [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine		25.00%