XML 44 R32.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Investments, Summary of Investments (Details) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Available-for-sale Securities [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | $ 1,502,739 |  | $ 911,594
Gross unrealized gains |  | 41 |  | 14
Gross unrealized losses |  | (3,942) |  | (3,072)
Estimated fair value |  | 1,498,838 |  | 908,536
Available-for-sale Securities [Member] | Securities with Maturity of One Year or Less [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | 1,188,558 |  | 643,193
Gross unrealized gains |  | 25 |  | 6
Gross unrealized losses |  | (1,852) |  | (1,103)
Estimated fair value |  | 1,186,731 |  | 642,096
Available-for-sale Securities [Member] | Securities with Maturity of More than One Year [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | 314,181 |  | 268,401
Gross unrealized gains |  | 16 |  | 8
Gross unrealized losses |  | (2,090) |  | (1,969)
Estimated fair value |  | 312,107 |  | 266,440
Corporate Debt Securities [Member] | Securities with Maturity of One Year or Less [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | 841,397 | [2] | 500,599
Gross unrealized gains |  | 23 |  | 2
Gross unrealized losses |  | (1,264) |  | (752)
Estimated fair value |  | 840,156 |  | 499,849
Corporate Debt Securities [Member] | Securities with Maturity of More than One Year [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | 240,208 |  | 148,663
Gross unrealized gains |  | 16 |  | 8
Gross unrealized losses |  | (1,420) |  | (1,059)
Estimated fair value |  | 238,804 |  | 147,612
Debt Securities issued by U.S. Government Agencies [Member] | Securities with Maturity of One Year or Less [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | 143,008 |  | 83,926
Gross unrealized gains |  | 2 |  | 0
Gross unrealized losses |  | (169) |  | (212)
Estimated fair value |  | 142,841 |  | 83,714
Debt Securities issued by U.S. Government Agencies [Member] | Securities with Maturity of More than One Year [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | 32,435 |  | 52,779
Gross unrealized gains |  | 0 |  | 0
Gross unrealized losses |  | (109) |  | (168)
Estimated fair value |  | 32,326 |  | 52,611
Debt Securities issued by the U.S. Treasury [Member] | Securities with Maturity of One Year or Less [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | 154,280 | [2] | 29,428
Gross unrealized gains |  | 0 |  | 0
Gross unrealized losses |  | (89) |  | (17)
Estimated fair value |  | 154,191 |  | 29,411
Debt Securities issued by the U.S. Treasury [Member] | Securities with Maturity of More than One Year [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost |  | 9,872 | [1] | 1,409
Gross unrealized gains |  | 0 |  | 0
Gross unrealized losses |  | (10) |  | (2)
Estimated fair value |  | 9,862 |  | 1,407
Debt Securities issued by States of the U.S. and Political Subdivisions of the States [Member] | Securities with Maturity of One Year or Less [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1],[2] | 49,873 |  | 29,240
Gross unrealized gains |  | 0 |  | 4
Gross unrealized losses |  | (330) |  | (122)
Estimated fair value |  | 49,543 |  | 29,122
Debt Securities issued by States of the U.S. and Political Subdivisions of the States [Member] | Securities with Maturity of More than One Year [Member] |  |  |  |
Summary of Investments [Abstract] |  |  |  |
Cost | [1] | 31,666 |  | 65,550
Gross unrealized gains |  | 0 |  | 0
Gross unrealized losses |  | (551) |  | (740)
Estimated fair value |  | $ 31,115 |  | $ 64,810
[1] | Our available-for-sale securities are held at amortized cost.
[2] | Includes investments classified as cash equivalents on our condensed consolidated balance sheet.

X
- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentSecondaryCategorizationAxis=ions_SecuritiesWithMaturityOfOneYearOrLessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentSecondaryCategorizationAxis=ions_SecuritiesWithMaturityOfMoreThanOneYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |