Amount of amortization expense attributable to the sale of future royalties.

No definition available.

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- Definition

Amount of interest expense using the effective interest rate method related to the sale of future royalties.

+ References

No definition available.

+ Details

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- Definition

Amount, after accumulated amortization, of the unamortized liability related to the sale of future royalties, pursuant to a royalty purchase agreement, that the Company is entitled to receive under collaboration agreements with Biogen and Novartis. The balance will be amortized over the estimated life of the arrangement using the effective interest rate method.

+ References

No definition available.

+ Details

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- Definition

+ References

No definition available.

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- Definition

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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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
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- 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
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- 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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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- 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-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of royalty payments made during the period under a royalty purchase agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- 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

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
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-Name Accounting Standards Codification
-Section 50
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
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-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-6

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Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2024
Royalty Revenue Monetization [Abstract]
Royalty payments to Royalty Pharma	$ (12,891)	$ (6,623)
Interest expense related to sale of future royalties	18,670	$ 17,806
Liability related to sale of future royalties, net - Non-current	536,141			$ 542,212
Royalty Purchase Agreement [Member]
Royalty Revenue Monetization [Abstract]
Upfront payment received			$ 500,000
Maximum amount of payments receivable for additional milestones	$ 625,000
Transaction costs			$ 10,400
Effective interest rate	13.50%	13.50%
Liability related to sale of future royalties, net	$ 542,212
Royalty payments to Royalty Pharma	(12,891)
Interest expense related to sale of future royalties	18,670
Amortization of issuance costs related to sale of future royalties	152
Liability related to sale of future royalties, net	548,143
Liability related to sale of future royalties, net - Non-current	536,141
Royalty Purchase Agreement [Member] \| Other Current Liabilities [Member]
Royalty Revenue Monetization [Abstract]
Less: Current portion	(12,002)
Royalty Purchase Agreement [Member] \| SPINRAZA [Member]
Royalty Revenue Monetization [Abstract]
Maximum amount of annual sales on which royalty payments are paid	$ 1,500,000
Royalty Purchase Agreement [Member] \| 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	$ 475,000
Royalty Purchase Agreement [Member] \| 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	$ 550,000
Royalty Purchase Agreement [Member] \| Pelacarsen [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine	25.00%