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v3.19.3.a.u2

Organization and Significant Accounting Policies, Basic and Diluted Net Income per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended
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Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Jun. 30, 2017 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Basic Net Income per Share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic net income (loss) per share (in dollars per share) | $ 1.31 | [1],[2] | $ 0.19 | [1],[2] | $ (0.01) | [1],[2] | $ 0.63 | [1],[2] | $ 2.32 | [1],[2] | $ (0.03) | [1],[2] | $ (0.29) | [1],[2] | $ (0.01) | [1],[2] |  | $ 2.12 | $ 2.09 | $ 0.15
Net income (loss) | $ 184,415 |  | $ 26,163 |  | $ (876) |  | $ 84,443 |  | $ 320,078 |  | $ (4,559) |  | $ (40,358) |  | $ (1,420) |  |  | $ 294,146 | $ 273,741 | $ 346
Net income available to Ionis common stockholders | $ 183,795 |  | $ 26,158 |  | $ (933) |  | $ 87,543 |  | $ 319,694 |  | $ (4,563) |  | $ (37,932) |  | $ (1,212) |  |  | $ 296,563 | $ 276,868 | $ 18,792
Shares used in computing basic net income per share (in shares) | 140,583 |  | 140,551 |  | 140,247 |  | 138,582 |  | 137,699 |  | 137,346 |  | 128,712 |  | 125,330 |  |  | 139,998 | 132,320 | 124,016
Income available to Ionis common shareholders, plus assumed conversions | $ 196,485 |  | $ 26,158 |  |  |  | $ 87,543 |  | $ 330,439 |  |  |  |  |  |  |  |  | $ 296,563 | $ 276,868 | $ 18,792
Shares issuable related to our Employee Stock Purchase Plan (in shares) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 18 | 6 | 4
Shares used in computing diluted net income per share (in shares) | 153,303 |  | 143,408 |  |  |  | 141,537 |  | 149,856 |  |  |  |  |  |  |  |  | 142,872 | 134,056 | 126,098
Diluted net income per share (in dollars per share) | $ 1.28 | [2],[3] | $ 0.18 | [2],[3],[4] | $ (0.01) | [2] | $ 0.62 | [2],[3],[4] | $ 2.21 | [2],[3] | $ (0.03) | [2] | $ (0.29) | [2] | $ (0.01) | [2] |  | $ 2.08 | $ 2.07 | $ 0.15
Stock Options [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic Net Income per Share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issuable related to stock-based compensation (in shares) | 1,467 |  | 1,993 |  |  |  | 2,252 |  | 1,254 |  |  |  |  |  |  |  |  | 2,090 | 1,216 | 1,619
Restricted Stock Awards [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic Net Income per Share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issuable related to stock-based compensation (in shares) | 848 |  | 844 |  |  |  | 665 |  | 636 |  |  |  |  |  |  |  |  | 766 | 514 | 459
Ionis [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic Net Income per Share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income (loss) | $ 121,552 |  | $ 49,930 |  | $ 27,311 |  | $ 63,697 |  | $ 372,913 |  | $ 43,226 |  | $ 5,882 |  | $ 18,785 |  |  | $ 262,490 | $ 440,806 | $ 110,776
Preferred Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic Net Income per Share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average shares owned in Akcea (in shares) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 15,748
Basic net income (loss) per share (in dollars per share) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (1.80)
Net income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (28,346)
Akcea [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic Net Income per Share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 34,073 | $ (163,938) | $ (91,984)
Akcea [Member] | Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic Net Income per Share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average shares owned in Akcea (in shares) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 70,100 | 59,812 | 20,669
Basic net income (loss) per share (in dollars per share) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.49 | $ (2.74) | $ (3.08)
Net income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 34,073 | $ (163,938) | $ (63,638)
Akcea [Member] | Preferred Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic Net Income per Share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6.00% |  |  |
Conversion ratio |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | converted into common stock on a 1:1 basis |  |
[1] | As discussed in Note 1, Organization and Significant Accounting Policies, we compute basic net income (loss) per share by dividing the total net income (loss) attributable to our common stockholders by our weighted-average number of common shares outstanding during the period. Our basic net income (loss) per share calculation for each of the quarters in 2019 and 2018 considered our net income for Ionis on a stand-alone basis plus our share of Akcea’s net loss for the period. To calculate the portion of Akcea’s net loss attributable to our ownership, we multiplied Akcea’s loss per share by the weighted average shares we owned in Akcea during the period. As a result of this calculation, our total net income (loss) available to Ionis common stockholders for the calculation of net income (loss) per share is different than net income (loss) attributable to Ionis Pharmaceuticals, Inc. common stockholders in the consolidated statements of operations.
[2] | We computed net income (loss) per share independently for each of the quarters presented. Therefore, the sum of the quarterly net income (loss) per share will not necessarily equal the total for the year.
[3] | We had net income available to Ionis common stockholders for the following periods. As a result, we computed diluted net income per share using the weighted-average number of common shares and dilutive common equivalent shares outstanding during those periods.
[4] | For the three months ended March 31, 2019 and September 30, 2019, the calculation excluded the 1 percent notes because the effect on diluted earnings per share was anti-dilutive.

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