Collaborative Arrangements and Licensing Agreements, Strategic Partnerships - Biogen (IONIS-DMPK-2.5) (Details) $ in Millions	Dec. 31, 2016 USD ($)
IONIS-DMPK-2.5 [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Cumulative payments received	$ 39

Cumulative amount of payments received under the collaboration agreement as of the end of the reporting period.

No definition available.

Name:	ions_CumulativePaymentsReceived
Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant