0000874015-24-000142 | 10-Q | XBRL Viewer | Ionis Pharmaceuticals INC

Assets Measured at Fair Value on a Recurring Basis

The following tables present the major security types we held at March 31, 2024 and December 31, 2023 that we regularly measure and carry at fair value. The following tables segregate each security type by the level within the fair value hierarchy of the valuation techniques we utilized to determine the respective security’s fair value (in thousands):

	At March 31, 2024		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Cash equivalents (1)	$	263,639	$	263,639	$	—
Corporate debt securities (2)		775,753		—		775,753
Debt securities issued by U.S. government agencies (3)		294,346		—		294,346
Debt securities issued by the U.S. Treasury (3)		785,030		785,030		—
Debt securities issued by states of the U.S. and political subdivisions of the states (3)		16,386		—		16,386
Publicly traded equity securities included in other current assets (4)		8,460		8,460		—
Total	$	2,143,614	$	1,057,129	$	1,086,485

	At December 31, 2023		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Cash equivalents (1)	$	185,424	$	185,424	$	—
Corporate debt securities (5)		801,228		—		801,228
Debt securities issued by U.S. government agencies (3)		334,828		—		334,828
Debt securities issued by the U.S. Treasury (3)		807,679		807,679		—
Debt securities issued by states of the U.S. and political subdivisions of the states (3)		21,155		—		21,155
Publicly traded equity securities included in other current assets (4)		6,301		6,301		—
Total	$	2,156,615	$	999,404	$	1,157,211

The following footnotes reference lines in our condensed consolidated balance sheets:

(1)	Included in cash and cash equivalents.

(2)	$14.2 million was included in cash and cash equivalents, with the difference included in short-term investments.

(3)	Included in short-term investments.

(4)	Included in other current assets.

(5)	$33.0 million was included in cash and cash equivalents, with the difference included in short-term investments.

Investments, Summary of Investments (Details)
$ in Thousands

3 Months Ended

Mar. 31, 2024

USD ($)

Company

Dec. 31, 2023

USD ($)

Ownership Interests in Private and Public Companies [Abstract]

Number of private companies in which there is an equity ownership interest of less than 20% | Company

Number of public companies in which there is an equity ownership interest of less than 20% | Company

Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]

$ 1,307,024

$ 1,316,219

178

415

(3,848)

(5,238)

Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]

1,303,354

1,311,396

569,655

651,628

672

3,063

(2,166)

(1,197)

Available-for-sale Debt Securities [Abstract]

568,161

653,494

1,876,679

1,967,847

850

3,478

(6,014)

(6,435)

1,871,515

1,964,890

Equity Securities [Abstract]

35,012

25,320

25,237

(8,881)

(10,957)

Available-for-sale Debt and Equity Securities [Abstract]

51,451

49,292

1,911,691

2,002,859

26,170

28,715

(14,895)

(17,392)

Corporate Debt Securities [Member]

1,922,966

2,014,182

Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]

^[1]

529,593

559,967

157

(1,990)

(2,625)

Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]

527,690

557,499

248,548

243,151

405

1,270

(890)

(692)

Debt Securities Issued by U.S. Government Agencies [Member]

248,063

243,729

Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]

179,632

224,711

(409)

(611)

Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]

179,247

224,164

115,152

110,138

134

547

(187)

(21)

Debt Securities Issued by the U.S. Treasury [Member]

115,099

110,664

Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]

^[1]

582,782

513,784

152

(1,372)

(1,889)

Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]

581,448

512,047

204,535

294,873

133

1,239

(1,086)

(480)

Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]

203,582

295,632

Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]

15,017

17,757

(77)

(113)

Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]

14,969

17,686

1,420

3,466

(3)

(4)

Publicly Traded Equity Securities [Member]

1,417

3,469

Equity Securities [Abstract]

^[2]

11,897

319

236

(3,756)

(5,832)

Available-for-sale Debt and Equity Securities [Abstract]

8,460

6,301

Unrealized gain on equity securities

2,200

Privately Held Equity Securities [Member]

Equity Securities [Abstract]

^[3]

23,115

25,001

(5,125)

Available-for-sale Debt and Equity Securities [Abstract]

42,991

$ 42,991

Unrealized gain on equity securities

$ 0

[1]	Includes investments classified as cash equivalents in our condensed consolidated balance sheets.
[2]	Our publicly traded equity securities are included in other current assets. We recognize publicly traded equity securities at fair value. In the three months ended March 31, 2024, we recorded a $2.2 million net unrealized gain in our condensed consolidated statements of operations related to changes in the fair value of our investments in publicly traded companies.
[3]	Our privately held equity securities are included in deposits and other assets. We recognize our privately held equity securities at cost minus impairments, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer, which are Level 3 inputs. In the three months ended March 31, 2024, there were no changes in the fair value of our investments in privately held companies.

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	145,844,719	144,340,526
Common stock, shares outstanding (in shares)	145,844,719	144,340,526
1.75 Percent Convertible Senior Notes [Member]
LIABILITIES AND STOCKHOLDERS' EQUITY
Interest rate on convertible senior notes	1.75%
0 Percent Convertible Senior Notes [Member]
LIABILITIES AND STOCKHOLDERS' EQUITY
Interest rate on convertible senior notes	0.00%	0.00%
0.125 Percent Convertible Senior Notes [Member]
LIABILITIES AND STOCKHOLDERS' EQUITY
Interest rate on convertible senior notes	0.125%	0.125%

Supplemental Financial Data (Tables)

3 Months Ended

Mar. 31, 2024

Supplemental Financial Data [Abstract]

Inventories

Our inventory consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Raw materials:
Raw materials - clinical	$	23,317	$	20,985
Raw materials - commercial		705		1,809
Total raw materials		24,022		22,794
Work in process		6,037		5,477
Finished goods		200		154
Total inventories	$	30,259	$	28,425

Accrued Liabilities

Our accrued liabilities consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Clinical development expenses	$	75,929	$	105,967
In-licensing expenses		6,436		7,454
Commercial expenses		4,739		4,875
Other miscellaneous expenses		18,944		29,598
Total accrued liabilities	$	106,048	$	147,894

Collaborative Arrangements and Licensing Agreements

3 Months Ended

Mar. 31, 2024

Collaborative Arrangements and Licensing Agreements [Abstract]

Collaborative Arrangements and Licensing Agreements

5. Collaborative Arrangements and Licensing Agreements

Below, we have included our AstraZeneca and Biogen collaborations, which are the collaborations with substantive changes during 2024 from those included in Part IV, Item 15, Note 4, Collaborative Arrangements and Licensing Agreements, of our audited financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2023.

AstraZeneca

We have two collaborations with AstraZeneca, one focused on the joint development and commercialization of WAINUA for the treatment of transthyretin amyloidosis, or ATTR, and one focused on the treatment of cardiovascular, renal and metabolic diseases. From inception through March 31, 2024, we have received nearly $910 million from these collaborations.

In January 2024, we and AstraZeneca launched WAINUA in the U.S. for the treatment of adults with polyneuropathy caused by hereditary transthyretin amyloidosis, or ATTRv-PN. As a result, we began earning royalties from WAINUA sales, which we recognize as commercial revenue in our condensed consolidated statements of operations. We will achieve the next payment of up to $30 million upon regulatory approval of WAINUA for ATTRv-PN in the European Union, or EU, under this collaboration.

During the three months ended March 31, 2024 and 2023, we earned the following revenue from our relationship with AstraZeneca (in thousands, except percentage amounts):

	Three Months Ended March 31,
	2024			2023
Revenue from our relationship with AstraZeneca	$	11,685		$	24,425
Percentage of total revenue		10	%		19	%

Our condensed consolidated balance sheet at March 31, 2024 included deferred contract revenue of $1.9 million from our relationship with AstraZeneca. We did not have any deferred contract revenue from our relationship with AstraZeneca at December 31, 2023.

Biogen

We have several strategic collaborations with Biogen focused on using antisense technology to advance the treatment of neurological disorders. We developed and licensed to Biogen SPINRAZA, our approved medicine to treat people with spinal muscular atrophy, or SMA. QALSODY, our medicine to treat patients with superoxide dismutase 1 amyotrophic lateral sclerosis, or SOD1-ALS, received accelerated approval in the U.S. in April 2023. In addition, we and Biogen are currently developing numerous other investigational medicines to treat neurodegenerative diseases, including medicines in development to treat people with amyotrophic lateral sclerosis, or ALS, SMA, Angelman Syndrome, or AS, Alzheimer’s disease, or AD, and Parkinson’s disease, or PD. In addition to these medicines, our collaborations with Biogen include a substantial research pipeline that addresses a broad range of neurological diseases. From inception through March 31, 2024, we have received more than $3.8 billion in payments from our Biogen collaborations, including payments to purchase our stock.

During the three months ended March 31, 2024 and 2023, we earned the following revenue from our relationship with Biogen (in thousands, except percentage amounts):

	Three Months Ended March 31,
	2024			2023
Revenue from our relationship with Biogen	$	59,236		$	70,501
Percentage of total revenue		50	%		54	%

Our condensed consolidated balance sheets at March 31, 2024 and December 31, 2023 included deferred contract revenue of $287.2 million and $307.4 million, respectively, from our relationship with Biogen.

Organization and Basis of Presentation (Policies)	3 Months Ended
Organization and Basis of Presentation (Policies)	Mar. 31, 2024
Organization and Basis of Presentation [Abstract]
Basis of Presentation	We prepared the unaudited interim condensed consolidated financial statements for the three months ended March 31, 2024 and 2023 on the same basis as the audited financial statements for the year ended December 31, 2023. We included all normal recurring adjustments in the financial statements, which we considered necessary for a fair presentation of our financial position at such dates and our operating results and cash flows for those periods. Our operating results for the interim periods may not be indicative of what our operating results will be for the entire year. For more complete financial information, these financial statements, and notes thereto, should be read in conjunction with the audited financial statements for the year ended December 31, 2023 included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission, or SEC.
Consolidation	In our condensed consolidated financial statements, we included the accounts of Ionis Pharmaceuticals, Inc. and the consolidated results of our wholly owned subsidiary, Akcea Therapeutics, Inc. and its wholly owned subsidiaries (“we”, “us” or “our”).
Segment Information	We operate as a single segment, Ionis operations, because our chief decision maker reviews operating results on an aggregate basis and manages our operations as a single operating segment.
Use of Estimates	Use of Estimates We prepare our condensed consolidated financial statements in conformity with accounting principles generally accepted in the United States, or U.S., that require us to make estimates and assumptions that affect the amounts reported in our condensed consolidated financial statements and accompanying notes. Actual results could differ from our estimates.

Supplemental Financial Data [Abstract]

Disclosure of accounting policy for segment reporting.

+ References + Details

Liability Related to Sale of Future Royalties (Tables)

3 Months Ended

Mar. 31, 2024

The following table sets forth information on our liability related to sale of future royalties (in thousands):

Proceeds from sale of future royalties in January 2023	$	500,000
Issuance costs related to sale of future royalties		(10,434	)
Royalty payments to Royalty Pharma		(44,628	)
Interest expense related to sale of future royalties		68,238
Amortization of issuance costs related to sale of future royalties		560
Net liability related to sale of future royalties as of December 31, 2023		513,736
Royalty payments to Royalty Pharma		(6,623	)
Interest expense related to sale of future royalties		17,806
Amortization of issuance costs related to sale of future royalties		153
Net liability related to sale of future royalties as of March 31, 2024	$	525,072

Supplemental Financial Data

3 Months Ended

Mar. 31, 2024

Supplemental Financial Data

3. Supplemental Financial Data

Inventories

Our inventory consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Raw materials:
Raw materials - clinical	$	23,317	$	20,985
Raw materials - commercial		705		1,809
Total raw materials		24,022		22,794
Work in process		6,037		5,477
Finished goods		200		154
Total inventories	$	30,259	$	28,425

Accrued Liabilities

Our accrued liabilities consisted of the following (in thousands):

	March 31, 2024		December 31, 2023
Clinical development expenses	$	75,929	$	105,967
In-licensing expenses		6,436		7,454
Commercial expenses		4,739		4,875
Other miscellaneous expenses		18,944		29,598
Total accrued liabilities	$	106,048	$	147,894

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Operating activities:
Net loss	$ (142,803)	$ (124,323)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,547	2,604
Amortization of right-of-use operating lease assets	2,465	2,395
Amortization of other assets	639	607
Amortization of discount on investments, net	(9,257)	(5,042)
Amortization of debt issuance costs	1,667	1,486
Non-cash royalty revenue related to sale of royalties	(6,623)	0
Non-cash interest related to sale of future royalties	17,806	15,363
Stock-based compensation expense	31,340	26,948
Loss (gain) on investments	(2,332)	529
Non-cash losses related to other assets	133	445
Changes in operating assets and liabilities:
Contracts receivable	92,638	11,624
Inventories	(1,834)	(167)
Other current and long-term assets	13,381	5,312
Income taxes payable	59	11,037
Accounts payable	(13,869)	(10,295)
Accrued compensation	(46,190)	(31,018)
Accrued liabilities and other current liabilities	(42,887)	(28,460)
Deferred contract revenue	(46,818)	(13,037)
Net cash used in operating activities	(149,938)	(133,992)
Investing activities:
Purchases of short-term investments	(519,001)	(688,278)
Proceeds from sale of short-term investments	600,836	374,363
Purchases of property, plant and equipment	(4,493)	(10,472)
Acquisition of licenses and other assets, net	(1,237)	(1,253)
Net cash provided by (used in) investing activities	76,105	(325,640)
Financing activities:
Proceeds from equity, net	23,609	2,560
Proceeds from sale of future royalties	0	500,000
Payments of transaction costs related to sale of future royalties	0	(10,434)
Principal payments on mortgage debt	(39)	(39)
Net cash provided by financing activities	23,570	492,087
Effects of exchange rates on cash	(114)	104
Net increase (decrease) in cash and cash equivalents	(50,377)	32,559
Cash and cash equivalents at beginning of period	399,266	276,472	$ 276,472
Cash and cash equivalents at end of period	348,889	309,031	$ 399,266
Supplemental disclosures of cash flow information:
Interest paid	95	89
Income taxes paid	13	293
Supplemental disclosures of non-cash investing and financing activities:
Amounts accrued for capital and patent expenditures	$ 924	$ 3,058

Organization and Basis of Presentation (Details)	3 Months Ended
Organization and Basis of Presentation (Details)	Mar. 31, 2024 Segment
Organization and Basis of Presentation [Abstract]
Number of operating segments	1

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 348,889	$ 399,266
Short-term investments	1,857,327	1,931,935
Contracts receivable	5,140	97,778
Inventories	30,259	28,425
Other current assets	174,060	184,449
Total current assets	2,415,675	2,641,853
Property, plant and equipment, net	72,795	71,043
Right-of-use assets	169,431	171,896
Deposits and other assets	106,027	105,280
Total assets	2,763,928	2,990,072
Current liabilities:
Accounts payable	13,082	26,027
Accrued compensation	21,537	67,727
Accrued liabilities	106,048	147,894
Income taxes payable	2,210	2,151
0.125 percent convertible senior notes, net	44,377	44,332
Current portion of deferred contract revenue	130,406	151,128
Other current liabilities	9,988	8,831
Total current liabilities	327,648	448,090
Long-term deferred contract revenue	215,088	241,184
Liability related to sale of future royalties, net	525,072	513,736
Long-term lease liabilities	168,674	170,875
Long-term obligations	41,800	41,836
Total liabilities	2,467,413	2,603,386
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized, 145,844,719 and 144,340,526 shares issued and outstanding at March 31, 2024 (unaudited) and December 31, 2023, respectively	146	144
Additional paid-in capital	2,270,047	2,215,098
Accumulated other comprehensive loss	(34,964)	(32,645)
Accumulated deficit	(1,938,714)	(1,795,911)
Total stockholders' equity	296,515	386,686
Total liabilities and stockholders' equity	2,763,928	2,990,072
1.75 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	562,964	562,285
0 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	$ 626,167	$ 625,380

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue:
Revenue	$ 119,497	$ 130,524
Expenses:
Cost of sales	2,151	1,343
Research, development and patent	214,215	197,813
Selling, general and administrative	52,644	45,516
Total operating expenses	269,010	244,672
Loss from operations	(149,513)	(114,148)
Other income (expense):
Investment income	26,285	18,627
Interest expense	(4,151)	(1,608)
Interest expense related to sale of future royalties	(17,959)	(15,515)
Gain (loss) on investments	2,333	(529)
Other income	277	230
Loss before income tax expense	(142,728)	(112,943)
Income tax expense	(75)	(11,380)
Net loss	$ (142,803)	$ (124,323)
Basic net loss per share (in dollars per share)	$ (0.98)	$ (0.87)
Diluted net loss per share (in dollars per share)	$ (0.98)	$ (0.87)
Shares used in computing basic net loss per share (in shares)	145,538	142,735
Shares used in computing diluted net loss per share (in shares)	145,538	142,735
Commercial Revenue [Member]
Revenue:
Revenue	$ 59,593	$ 67,768
SPINRAZA Royalties [Member]
Revenue:
Revenue	38,455	50,247
WAINUA Royalties [Member]
Revenue:
Revenue	1,125	0
Other Commercial Revenue [Member]
Revenue:
Revenue	20,013	17,521
Research and Development Revenue [Member]
Revenue:
Revenue	59,904	62,756
Collaborative Agreement Revenue [Member]
Revenue:
Revenue	49,345	38,334
WAINUA Joint Development Revenue [Member]
Revenue:
Revenue	$ 10,559	$ 24,422

Convertible Debt

3 Months Ended

Mar. 31, 2024

Convertible Debt

12. Convertible Debt

1.75 Percent Convertible Senior Notes

In 2023, we completed a $575.0 million offering of convertible senior notes and used $488.2 million of the net proceeds from the issuance of the 1.75% Notes to repurchase $504.4 million in principal of our 0.125% Notes. We expect to use the remaining net proceeds to settle the 0.125% Notes that remain outstanding.

At March 31, 2024, we had the following 1.75% Notes outstanding (in millions except interest rate and price per share data):

	1.75% Notes
Outstanding principal balance	$	575.0
Unamortized debt issuance costs	$	12.0
Maturity date	June 2028
Interest rate		1.75	%
Effective interest rate		2.3	%
Conversion price per share	$	53.73
Total shares of common stock subject to conversion		10.7

0 Percent Convertible Senior Notes and Call Spread

At March 31, 2024, we had the following 0% Notes outstanding (in millions except interest rate and price per share data):

	0% Notes
Outstanding principal balance	$	632.5
Unamortized debt issuance costs	$	6.3
Maturity date	April 2026
Interest rate		0	%
Effective interest rate		0.5	%
Conversion price per share	$	57.84
Effective conversion price per share with call spread	$	76.39
Total shares of common stock subject to conversion		10.9

In conjunction with the 2021 offering, we entered into a call spread transaction, which was comprised of purchasing note hedges and selling warrants, to minimize the impact of potential economic dilution upon conversion of our 0% Notes by increasing the effective conversion price on our 0% Notes. We increased our effective conversion price to $76.39 with the same number of underlying shares as our 0% Notes. The call spread cost us $46.9 million, of which $136.7 million was for the note hedge purchase, offset by $89.8 million we received for selling the warrants. Similar to our 0% Notes, our note hedges are subject to adjustment. Additionally, our note hedges are exercisable upon conversion of the 0% Notes. The note hedges will expire upon maturity of the 0% Notes, or April 2026. The note hedges and warrants are separate transactions and are not part of the terms of our 0% Notes. The holders of the 0% Notes do not have any rights with respect to the note hedges and warrants.

We recorded the amount we paid for the note hedges and the amount we received for the warrants in additional paid-in capital in our condensed consolidated balance sheets. Refer to Part IV, Item 15, Note 1, Organization and Significant Accounting Policies, of our audited financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2023 for our Call Spread accounting policy. We reassess our ability to continue to classify the note hedges and warrants in shareholders’ equity at each reporting period.

0.125 Percent Convertible Senior Notes and Call Spread

As discussed above, in 2023, we repurchased $504.4 million of our 0.125% Notes.

At March 31, 2024, we had the following 0.125% Notes outstanding with interest payable semi-annually (in millions except interest rate and price per share data):

	0.125% Notes
Outstanding principal balance	$	44.5
Unamortized debt issuance costs	$	0.1
Maturity date	December 2024
Interest rate		0.125	%
Effective interest rate		0.5	%
Conversion price per share	$	83.28
Effective conversion price per share with call spread	$	123.38
Total shares of common stock subject to conversion, excluding shares related to 0.125% Notes that we have repurchased and are currently holding in treasury		0.5

In conjunction with the issuance of our 0.125% Notes in 2019, we entered into a call spread transaction, which was comprised of purchasing note hedges and selling warrants, to minimize the impact of potential economic dilution upon conversion of our 0.125% Notes by increasing the effective conversion price on our 0.125% Notes. We increased our effective conversion price to $123.38 with the same number of underlying shares as our 0.125% Notes. The call spread cost us $52.6 million, of which $108.7 million was for the note hedge purchase, offset by $56.1 million we received for selling the warrants. Similar to our 0.125% Notes, our note hedges are subject to adjustment. Additionally, our note hedges are exercisable upon conversion of the 0.125% Notes. The note hedges will expire upon maturity of the 0.125% Notes, or December 2024. The note hedges and warrants are separate transactions and are not part of the terms of our 0.125% Notes. The holders of the 0.125% Notes do not have any rights with respect to the note hedges and warrants. As of March 31, 2024, the note hedges and warrants remain outstanding.

We recorded the amount we paid for the note hedges and the amount we received for the warrants in additional paid-in capital in our condensed consolidated balance sheets. We reassess our ability to continue to classify the note hedges and warrants in shareholders’ equity at each reporting period.

Other Terms of Convertible Senior Notes

The 1.75%, 0% and 0.125% Notes are convertible under certain conditions, at the option of the note holders. We can settle conversions of the notes, at our election, in cash, shares of our common stock or a combination of both. We may not redeem the notes prior to maturity, and we do not have to provide a sinking fund for them. Holders of the notes may require us to purchase some or all of their notes upon the occurrence of certain fundamental changes, as set forth in the indentures governing the notes, at a purchase price equal to 100 percent of the principal amount of the notes to be purchased, plus any accrued and unpaid interest.

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
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Contract Maturity of Available-for-Sale Securities

Significant Accounting Policies	3 Months Ended
Significant Accounting Policies	Mar. 31, 2024
Significant Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Our significant accounting policies have not changed substantially from those included in our Annual Report on Form 10-K for the year ended December 31, 2023. Recently Adopted Accounting Standards We do not expect any recently issued accounting standards to have a material impact to our financial results.

Investments (Tables)

3 Months Ended

Mar. 31, 2024

Investments [Abstract]

The following table summarizes the contract maturity of the available-for-sale securities we held as of March 31, 2024:

One year or less	69	%
After one year but within two years	26	%
After two years but within three and a half years	5	%
Total	100	%

Summary of Investments

The following is a summary of our investments (in thousands):

	Amortized		Gross Unrealized					Estimated
March 31, 2024	Cost		Gains		Losses			Fair Value
Available-for-sale debt securities:
Corporate debt securities (1)	$	529,593	$	87	$	(1,990	)	$	527,690
Debt securities issued by U.S. government agencies		179,632		24		(409	)		179,247
Debt securities issued by the U.S. Treasury (1)		582,782		38		(1,372	)		581,448
Debt securities issued by states of the U.S. and political subdivisions of the states		15,017		29		(77	)		14,969
Total debt securities with a maturity of one year or less		1,307,024		178		(3,848	)		1,303,354
Corporate debt securities		248,548		405		(890	)		248,063
Debt securities issued by U.S. government agencies		115,152		134		(187	)		115,099
Debt securities issued by the U.S. Treasury		204,535		133		(1,086	)		203,582
Debt securities issued by states of the U.S. and political subdivisions of the states		1,420		—		(3	)		1,417
Total debt securities with a maturity of more than one year		569,655		672		(2,166	)		568,161
Total available-for-sale debt securities	$	1,876,679	$	850	$	(6,014	)	$	1,871,515
Equity securities:
Publicly traded equity securities included in other current assets (2)	$	11,897	$	319	$	(3,756	)	$	8,460
Privately held equity securities included in deposits and other assets (3)		23,115		25,001		(5,125	)		42,991
Total equity securities		35,012		25,320		(8,881	)		51,451
Total available-for-sale debt and equity securities	$	1,911,691	$	26,170	$	(14,895	)	$	1,922,966

	Amortized		Gross Unrealized					Estimated
December 31, 2023	Cost		Gains		Losses			Fair Value
Available-for-sale debt securities:
Corporate debt securities (1)	$	559,967	$	157	$	(2,625	)	$	557,499
Debt securities issued by U.S. government agencies		224,711		64		(611	)		224,164
Debt securities issued by the U.S. Treasury (1)		513,784		152		(1,889	)		512,047
Debt securities issued by states of the U.S. and political subdivisions of the states		17,757		42		(113	)		17,686
Total debt securities with a maturity of one year or less		1,316,219		415		(5,238	)		1,311,396
Corporate debt securities		243,151		1,270		(692	)		243,729
Debt securities issued by U.S. government agencies		110,138		547		(21	)		110,664
Debt securities issued by the U.S. Treasury		294,873		1,239		(480	)		295,632
Debt securities issued by states of the U.S. and political subdivisions of the states		3,466		7		(4	)		3,469
Total debt securities with a maturity of more than one year		651,628		3,063		(1,197	)		653,494
Total available-for-sale debt securities	$	1,967,847	$	3,478	$	(6,435	)	$	1,964,890
Equity securities:
Publicly traded equity securities included in other current assets (2)	$	11,897	$	236	$	(5,832	)	$	6,301
Privately held equity securities included in deposits and other assets (3)		23,115		25,001		(5,125	)		42,991
Total equity securities		35,012		25,237		(10,957	)		49,292
Total available-for-sale debt and equity securities	$	2,002,859	$	28,715	$	(17,392	)	$	2,014,182

(1)	Includes investments classified as cash equivalents in our condensed consolidated balance sheets.

(2)

(3)

Temporarily Impaired Investments

The following is a summary of our investments we consider to be temporarily impaired at March 31, 2024 (in thousands, except for number of investments):

			Less than 12 Months of Temporary Impairment					More than 12 Months of Temporary Impairment					Total Temporary Impairment
	Number of Investments		Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses
Corporate debt securities		392	$	487,939	$	(1,361	)	$	96,219	$	(1,519	)	$	584,158	$	(2,880	)
Debt securities issued by U.S. government agencies		80		176,956		(360	)		12,375		(236	)		189,331		(596	)
Debt securities issued by the U.S. Treasury		64		588,958		(1,773	)		86,772		(685	)		675,730		(2,458	)
Debt securities issued by states of the U.S. and political subdivisions of the states		53		7,978		(22	)		5,703		(58	)		13,681		(80	)
Total temporarily impaired securities		589	$	1,261,831	$	(3,516	)	$	201,069	$	(2,498	)	$	1,462,900	$	(6,014	)

Liability Related to Sale of Future Royalties

3 Months Ended

Mar. 31, 2024

11. Liability Related to Sale of Future Royalties

In January 2023, we entered into a royalty purchase agreement with Royalty Pharma to monetize a portion of our future SPINRAZA and pelacarsen royalties we are entitled to under our arrangements with Biogen and Novartis, respectively. As a result, we received an upfront payment of $500 million and we are eligible to receive up to $625 million in additional milestone payments. Under the terms of the agreement, Royalty Pharma will receive 25 percent of our SPINRAZA royalty payments from 2023 through 2027, increasing to 45 percent of royalty payments in 2028, on up to $1.5 billion in annual sales. In addition, Royalty Pharma will receive 25 percent of any future royalty payments on pelacarsen, our medicine in development to treat patients with elevated lipoprotein(a)-driven cardiovascular disease. Royalty Pharma’s royalty interest in SPINRAZA will revert to us after total SPINRAZA royalty payments to Royalty Pharma reach either $475 million or $550 million, depending on the timing and occurrence of FDA approval of pelacarsen.

We recorded the upfront payment of $500 million as a liability related to the sale of future royalties, net of transaction costs of $10.4 million, which we are amortizing over the estimated life of the arrangement using the effective interest rate method. We recognize royalty revenue in the period in which the counterparty sells the related product and recognizes the related revenue. We record royalty payments made to Royalty Pharma as a reduction of the liability.

We determine the effective interest rate used to record interest expense under this agreement based on an estimate of future royalty payments to Royalty Pharma. As of March 31, 2024, the estimated effective interest rate under the agreement was 13.5 percent.

The following table sets forth information on our liability related to sale of future royalties (in thousands):

Proceeds from sale of future royalties in January 2023	$	500,000
Issuance costs related to sale of future royalties		(10,434	)
Royalty payments to Royalty Pharma		(44,628	)
Interest expense related to sale of future royalties		68,238
Amortization of issuance costs related to sale of future royalties		560
Net liability related to sale of future royalties as of December 31, 2023		513,736
Royalty payments to Royalty Pharma		(6,623	)
Interest expense related to sale of future royalties		17,806
Amortization of issuance costs related to sale of future royalties		153
Net liability related to sale of future royalties as of March 31, 2024	$	525,072

There are numerous factors, most of which are not within our control, that could materially impact the amount and timing of royalty payments from Biogen and Novartis, and result in changes to our estimate of future royalty payments to Royalty Pharma. Such factors include, but are not limited to, the commercial sales of SPINRAZA, the regulatory approval and commercial sales of pelacarsen, competing products or other significant events.

Collaborative Arrangements and Licensing Agreements, Biogen (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue	$ 119,497	$ 130,524
Biogen [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue	59,236	$ 70,501
Deferred contract revenue	$ 287,200		$ 307,400
Biogen [Member] \| Revenue [Member] \| Strategic Partner [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Concentration percentage	50.00%	54.00%
Biogen [Member] \| Minimum [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Cumulative payments received	$ 3,800,000

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Basic and Diluted Net Loss Per Share (Details)	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
0% Notes [Member]
Diluted Net Loss per Share [Abstract]
Interest rate on convertible senior notes	0.00%	0.00%	0.00%
0.125% Notes [Member]
Diluted Net Loss per Share [Abstract]
Interest rate on convertible senior notes	0.125%	0.125%	0.125%
1.75% Notes [Member]
Diluted Net Loss per Share [Abstract]
Interest rate on convertible senior notes	1.75%

Convertible Debt (Tables)

3 Months Ended

Mar. 31, 2024

1.75% Notes [Member]

Convertible Senior Notes

At March 31, 2024, we had the following 1.75% Notes outstanding (in millions except interest rate and price per share data):

	1.75% Notes
Outstanding principal balance	$	575.0
Unamortized debt issuance costs	$	12.0
Maturity date	June 2028
Interest rate		1.75	%
Effective interest rate		2.3	%
Conversion price per share	$	53.73
Total shares of common stock subject to conversion		10.7

0% Notes [Member]

Convertible Senior Notes

At March 31, 2024, we had the following 0% Notes outstanding (in millions except interest rate and price per share data):

	0% Notes
Outstanding principal balance	$	632.5
Unamortized debt issuance costs	$	6.3
Maturity date	April 2026
Interest rate		0	%
Effective interest rate		0.5	%
Conversion price per share	$	57.84
Effective conversion price per share with call spread	$	76.39
Total shares of common stock subject to conversion		10.9

0.125% Notes [Member]

Convertible Senior Notes

At March 31, 2024, we had the following 0.125% Notes outstanding with interest payable semi-annually (in millions except interest rate and price per share data):

	0.125% Notes
Outstanding principal balance	$	44.5
Unamortized debt issuance costs	$	0.1
Maturity date	December 2024
Interest rate		0.125	%
Effective interest rate		0.5	%
Conversion price per share	$	83.28
Effective conversion price per share with call spread	$	123.38
Total shares of common stock subject to conversion, excluding shares related to 0.125% Notes that we have repurchased and are currently holding in treasury		0.5

Revenues (Tables)

3 Months Ended

Mar. 31, 2024

Revenues [Abstract]

Revenues

During the three months ended March 31, 2024 and 2023, our revenues were comprised of the following (in thousands):

	Three Months Ended March 31,
	2024		2023
Revenue:
Commercial revenue:
SPINRAZA royalties	$	38,455	$	50,247
WAINUA royalties		1,125		—
Other commercial revenue:
TEGSEDI and WAYLIVRA revenue, net		8,628		6,478
Licensing and other royalty revenue		11,385		11,043
Total other commercial revenue		20,013		17,521
Total commercial revenue		59,593		67,768
Research and development revenue:
Collaborative agreement revenue		49,345		38,334
WAINUA joint development revenue		10,559		24,422
Total research and development revenue		59,904		62,756
Total revenue	$	119,497	$	130,524

Convertible Debt (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2021	Dec. 31, 2019	Mar. 31, 2023
1.75% Notes [Member]
Convertible Debt [Abstract]
Face amount of offering		$ 575.0
Repurchase of convertible senior notes		$ 488.2
Outstanding principal balance	$ 575.0
Unamortized debt issuance costs	$ 12.0
Maturity date	Jun. 30, 2028
Interest rate	1.75%
Effective interest rate	2.30%
Conversion price per share (in dollars per share)	$ 53.73
Total shares of common stock subject to conversion (in shares)	10.7
Percentage of principal amount used as purchase price upon occurrence of fundamental change	100.00%
0% Notes [Member]
Convertible Debt [Abstract]
Outstanding principal balance	$ 632.5
Unamortized debt issuance costs	$ 6.3
Maturity date	Apr. 30, 2026
Interest rate	0.00%	0.00%			0.00%
Effective interest rate	0.50%
Conversion price per share (in dollars per share)	$ 57.84
Effective conversion price per share with call spread (in dollars per share)	$ 76.39
Total shares of common stock subject to conversion (in shares)	10.9
Cost of call spread			$ 46.9
Purchase of note hedges			136.7
Proceeds from issuance of warrants			$ 89.8
Percentage of principal amount used as purchase price upon occurrence of fundamental change	100.00%
0.125% Notes [Member]
Convertible Debt [Abstract]
Repurchase of convertible senior notes		$ 504.4
Outstanding principal balance	$ 44.5
Unamortized debt issuance costs	$ 0.1
Maturity date	Dec. 31, 2024
Interest rate	0.125%	0.125%			0.125%
Effective interest rate	0.50%
Conversion price per share (in dollars per share)	$ 83.28
Effective conversion price per share with call spread (in dollars per share)	$ 123.38
Total shares of common stock subject to conversion (in shares)	0.5
Cost of call spread				$ 52.6
Purchase of note hedges				108.7
Proceeds from issuance of warrants				$ 56.1
Percentage of principal amount used as purchase price upon occurrence of fundamental change	100.00%

Investments, Contract Maturity of Available-for-Sale Securities (Details)	3 Months Ended
	Mar. 31, 2024
Contract Maturity of Available-for-Sale Securities [Abstract]
One year or less	69.00%
After one year but within two years	26.00%
After two years but within three and a half years	5.00%
Total	100.00%
Maximum contract maturity period, range 1	1 year
Maximum contract maturity period, range 2	2 years
Maximum contract maturity period, range 3	3 years 6 months
Percentage of available-for-sale securities with a maturity of less than two years	95.00%

Fair Value Measurements

3 Months Ended

Mar. 31, 2024

Fair Value Measurements

8. Fair Value Measurements

	At March 31, 2024		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Cash equivalents (1)	$	263,639	$	263,639	$	—
Corporate debt securities (2)		775,753		—		775,753
Debt securities issued by U.S. government agencies (3)		294,346		—		294,346
Debt securities issued by the U.S. Treasury (3)		785,030		785,030		—
Debt securities issued by states of the U.S. and political subdivisions of the states (3)		16,386		—		16,386
Publicly traded equity securities included in other current assets (4)		8,460		8,460		—
Total	$	2,143,614	$	1,057,129	$	1,086,485

	At December 31, 2023		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Cash equivalents (1)	$	185,424	$	185,424	$	—
Corporate debt securities (5)		801,228		—		801,228
Debt securities issued by U.S. government agencies (3)		334,828		—		334,828
Debt securities issued by the U.S. Treasury (3)		807,679		807,679		—
Debt securities issued by states of the U.S. and political subdivisions of the states (3)		21,155		—		21,155
Publicly traded equity securities included in other current assets (4)		6,301		6,301		—
Total	$	2,156,615	$	999,404	$	1,157,211

The following footnotes reference lines in our condensed consolidated balance sheets:

(1)	Included in cash and cash equivalents.

(2)	$14.2 million was included in cash and cash equivalents, with the difference included in short-term investments.

(3)	Included in short-term investments.

(4)	Included in other current assets.

(5)	$33.0 million was included in cash and cash equivalents, with the difference included in short-term investments.

Convertible Notes

Our 1.75% Notes, 0% Notes and 0.125% Notes had a fair value of $601.1 million, $627.8 million and $42.4 million at March 31, 2024, respectively. Our 1.75% Notes, 0% Notes and 0.125% Notes had a fair value of $661.1 million, $667.8 million and $42.4 million at December 31, 2023, respectively. We determine the fair value of our notes based on quoted market prices for these notes, which are Level 2 measurements because the notes do not trade regularly.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Supplemental Financial Data, Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accrued Liabilities [Abstract]
Clinical development expenses	$ 75,929	$ 105,967
In-licensing expenses	6,436	7,454
Commercial expenses	4,739	4,875
Other miscellaneous expenses	18,944	29,598
Total accrued liabilities	$ 106,048	$ 147,894

Significant Accounting Policies (Policies)	3 Months Ended
Significant Accounting Policies (Policies)	Mar. 31, 2024
Significant Accounting Policies [Abstract]
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards We do not expect any recently issued accounting standards to have a material impact to our financial results.

Investments, Investments Temporarily Impaired (Details) $ in Thousands	Mar. 31, 2024 USD ($) Investment
Temporarily Impaired Investments [Abstract]
Number of investments \| Investment	589
Estimated Fair Value [Abstract]
Less than 12 months of temporary impairment	$ 1,261,831
More than 12 months of temporary impairment	201,069
Total temporary impairment	1,462,900
Unrealized Losses [Abstract]
Less than 12 months of temporary impairment	(3,516)
More than 12 months of temporary impairment	(2,498)
Total temporary impairment	$ (6,014)
Corporate Debt Securities [Member]
Temporarily Impaired Investments [Abstract]
Number of investments \| Investment	392
Estimated Fair Value [Abstract]
Less than 12 months of temporary impairment	$ 487,939
More than 12 months of temporary impairment	96,219
Total temporary impairment	584,158
Unrealized Losses [Abstract]
Less than 12 months of temporary impairment	(1,361)
More than 12 months of temporary impairment	(1,519)
Total temporary impairment	$ (2,880)
Debt Securities Issued by U.S. Government Agencies [Member]
Temporarily Impaired Investments [Abstract]
Number of investments \| Investment	80
Estimated Fair Value [Abstract]
Less than 12 months of temporary impairment	$ 176,956
More than 12 months of temporary impairment	12,375
Total temporary impairment	189,331
Unrealized Losses [Abstract]
Less than 12 months of temporary impairment	(360)
More than 12 months of temporary impairment	(236)
Total temporary impairment	$ (596)
Debt Securities Issued by the U.S. Treasury [Member]
Temporarily Impaired Investments [Abstract]
Number of investments \| Investment	64
Estimated Fair Value [Abstract]
Less than 12 months of temporary impairment	$ 588,958
More than 12 months of temporary impairment	86,772
Total temporary impairment	675,730
Unrealized Losses [Abstract]
Less than 12 months of temporary impairment	(1,773)
More than 12 months of temporary impairment	(685)
Total temporary impairment	$ (2,458)
Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]
Temporarily Impaired Investments [Abstract]
Number of investments \| Investment	53
Estimated Fair Value [Abstract]
Less than 12 months of temporary impairment	$ 7,978
More than 12 months of temporary impairment	5,703
Total temporary impairment	13,681
Unrealized Losses [Abstract]
Less than 12 months of temporary impairment	(22)
More than 12 months of temporary impairment	(58)
Total temporary impairment	$ (80)

Revenues (Details) $ in Thousands	3 Months Ended		12 Months Ended
Revenues (Details) $ in Thousands	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2021 USD ($) Component PerformanceObligation
Revenues [Abstract]
Revenue	$ 119,497	$ 130,524
WAINUA (Eplontersen) Collaboration with AstraZeneca [Member]
Revenues [Abstract]
Upfront payment received			$ 200,000
Number of material components \| Component			4
Number of performance obligations \| PerformanceObligation			1
Transaction price			$ 200,000
Percentage of costs associated with ongoing global Phase 3 development program paid by AstraZeneca	55.00%
Commercial Revenue [Member]
Revenues [Abstract]
Revenue	$ 59,593	67,768
SPINRAZA Royalties [Member]
Revenues [Abstract]
Revenue	38,455	50,247
WAINUA Royalties [Member]
Revenues [Abstract]
Revenue	1,125	0
Other Commercial Revenue [Member]
Revenues [Abstract]
Revenue	20,013	17,521
TEGSEDI and WAYLIVRA Revenue, Net [Member]
Revenues [Abstract]
Revenue	8,628	6,478
Licensing and Other Royalty Revenue [Member]
Revenues [Abstract]
Revenue	11,385	11,043
Research and Development Revenue [Member]
Revenues [Abstract]
Revenue	59,904	62,756
Collaborative Agreement Revenue [Member]
Revenues [Abstract]
Revenue	49,345	38,334
WAINUA Joint Development Revenue [Member]
Revenues [Abstract]
Revenue	$ 10,559	$ 24,422

Organization and Basis of Presentation	3 Months Ended
Organization and Basis of Presentation	Mar. 31, 2024
Organization and Basis of Presentation [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Organization and Business Activity We incorporated in California on January 10, 1989. In conjunction with our initial public offering, we reorganized as a Delaware corporation in April 1991. We are a leader in the discovery and development of RNA-targeted therapeutics. Basis of Presentation We prepared the unaudited interim condensed consolidated financial statements for the three months ended March 31, 2024 and 2023 on the same basis as the audited financial statements for the year ended December 31, 2023. We included all normal recurring adjustments in the financial statements, which we considered necessary for a fair presentation of our financial position at such dates and our operating results and cash flows for those periods. Our operating results for the interim periods may not be indicative of what our operating results will be for the entire year. For more complete financial information, these financial statements, and notes thereto, should be read in conjunction with the audited financial statements for the year ended December 31, 2023 included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission, or SEC. In our condensed consolidated financial statements, we included the accounts of Ionis Pharmaceuticals, Inc. and the consolidated results of our wholly owned subsidiary, Akcea Therapeutics, Inc. and its wholly owned subsidiaries (“we”, “us” or “our”). We operate as a single segment, Ionis operations, because our chief decision maker reviews operating results on an aggregate basis and manages our operations as a single operating segment. Use of Estimates We prepare our condensed consolidated financial statements in conformity with accounting principles generally accepted in the United States, or U.S., that require us to make estimates and assumptions that affect the amounts reported in our condensed consolidated financial statements and accompanying notes. Actual results could differ from our estimates.

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2022	$ 142	$ 2,059,850	$ (57,480)	$ (1,429,625)	$ 572,887
Balance (in shares) at Dec. 31, 2022	142,058
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(124,323)	(124,323)
Change in unrealized losses, net of tax	0	0	8,393	0	8,393
Foreign currency translation	0	0	104	0	104
Issuance of common stock in connection with employee stock plans	$ 1	2,560	0	0	2,561
Issuance of common stock in connection with employee stock plans (in shares)	965
Stock-based compensation expense	$ 0	26,948	0	0	26,948
Balance at Mar. 31, 2023	$ 143	2,089,358	(48,983)	(1,553,948)	486,570
Balance (in shares) at Mar. 31, 2023	143,023
Balance at Dec. 31, 2023	$ 144	2,215,098	(32,645)	(1,795,911)	386,686
Balance (in shares) at Dec. 31, 2023	144,341
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(142,803)	(142,803)
Change in unrealized losses, net of tax	0	0	(2,205)	0	(2,205)
Foreign currency translation	0	0	(114)	0	(114)
Issuance of common stock in connection with employee stock plans	$ 2	23,609	0	0	23,611
Issuance of common stock in connection with employee stock plans (in shares)	1,504
Stock-based compensation expense	$ 0	31,340	0	0	31,340
Balance at Mar. 31, 2024	$ 146	$ 2,270,047	$ (34,964)	$ (1,938,714)	$ 296,515
Balance (in shares) at Mar. 31, 2024	145,845

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

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Basic and Diluted Net Loss Per Share [Abstract]

Basic and Diluted Net Loss Per Share (Policies)

3 Months Ended

Mar. 31, 2024

Basic and Diluted Net Loss Per Share

Basic net loss per share

We calculated our basic net loss per share for the three months ended March 31, 2024 and 2023 by dividing our net loss by our weighted-average number of common shares outstanding during the period.

Diluted net loss per share

For the three months ended March 31, 2024 and 2023, we incurred a net loss; therefore, we did not include dilutive common equivalent shares in the computation of diluted net loss per share because the effect would have been anti-dilutive. Common stock from the following would have had an anti-dilutive effect on net loss per share:

●

0 percent convertible senior notes, or 0% Notes;

●

Note hedges related to the 0% Notes;

●

0.125 percent convertible senior notes, or 0.125% Notes;

●

Note hedges related to the 0.125% Notes;

●

Dilutive stock options;

●

Unvested restricted stock units, or RSUs;

●

Unvested performance restricted stock units, or PRSUs; and

●

Employee Stock Purchase Plan, or ESPP.

For the three months ended March 31, 2024, common stock underlying the 1.75 percent convertible senior notes, or 1.75% Notes, would also have had an anti-dilutive effect on net loss per share.

Additionally as of March 31, 2024 and 2023, we had warrants related to our 0% and 0.125% Notes outstanding. We will include the shares issuable under these warrants in our calculation of diluted earnings per share when the average market price per share of our common stock for the reporting period exceeds the strike price of the warrants.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS [Abstract]
Net loss	$ (142,803)	$ (124,323)
Unrealized losses on debt securities, net of tax	(2,205)	8,393
Currency translation adjustment	(114)	104
Comprehensive loss	$ (145,122)	$ (115,826)

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Fair Value Measurements (Details) - USD ($)
$ in Thousands

Mar. 31, 2024

Dec. 31, 2023

Mar. 31, 2023

$ 1,871,515

$ 1,964,890

$ 51,451

$ 49,292

1.75% Notes [Member]

Interest rate on convertible senior notes

1.75%

0% Notes [Member]

Interest rate on convertible senior notes

0.00%

0.125% Notes [Member]

Interest rate on convertible senior notes

0.125%

Publicly Traded Equity Securities [Member]

$ 8,460

$ 6,301

Recurring Basis [Member]

Recurring Basis [Member] | Corporate Debt Securities [Member]

Cash equivalents

^[1]

263,639

185,424

Total

2,143,614

2,156,615

Recurring Basis [Member] | Corporate Debt Securities [Member] | Cash and Cash Equivalents [Member]

775,753

^[2]

801,228

^[3]

Recurring Basis [Member] | Debt Securities Issued by U.S. Government Agencies [Member]

14,200

33,000

Recurring Basis [Member] | Debt Securities Issued by the U.S. Treasury [Member]

^[4]

294,346

334,828

Recurring Basis [Member] | Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]

^[4]

785,030

807,679

Recurring Basis [Member] | Publicly Traded Equity Securities [Member] | Other Current Assets [Member]

^[4]

16,386

21,155

Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member]

^[5]

8,460

6,301

Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Corporate Debt Securities [Member]

Cash equivalents

263,639

185,424

Total

1,057,129

999,404

Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by U.S. Government Agencies [Member]

Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by the U.S. Treasury [Member]

Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]

785,030

807,679

Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Publicly Traded Equity Securities [Member]

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]

8,460

6,301

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 1.75% Notes [Member]

Cash equivalents

Total

1,086,485

1,157,211

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 0% Notes [Member]

Convertible notes

601,100

661,100

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 0.125% Notes [Member]

Convertible notes

627,800

667,800

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member]

Convertible notes

42,400

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by U.S. Government Agencies [Member]

775,753

801,228

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by the U.S. Treasury [Member]

294,346

334,828

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]

Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Publicly Traded Equity Securities [Member]

16,386

21,155

$ 0

[1]	Included in cash and cash equivalents.
[2]	$14.2 million was included in cash and cash equivalents, with the difference included in short-term investments.
[3]	$33.0 million was included in cash and cash equivalents, with the difference included in short-term investments.
[4]	Included in short-term investments.
[5]	Included in other current assets.

Revenues

3 Months Ended

Mar. 31, 2024

Revenues [Abstract]

Revenues

4. Revenues

During the three months ended March 31, 2024 and 2023, our revenues were comprised of the following (in thousands):

	Three Months Ended March 31,
	2024		2023
Revenue:
Commercial revenue:
SPINRAZA royalties	$	38,455	$	50,247
WAINUA royalties		1,125		—
Other commercial revenue:
TEGSEDI and WAYLIVRA revenue, net		8,628		6,478
Licensing and other royalty revenue		11,385		11,043
Total other commercial revenue		20,013		17,521
Total commercial revenue		59,593		67,768
Research and development revenue:
Collaborative agreement revenue		49,345		38,334
WAINUA joint development revenue		10,559		24,422
Total research and development revenue		59,904		62,756
Total revenue	$	119,497	$	130,524

Revenue Sources

The following are sources of revenue and when we typically recognize revenue.

Commercial Revenue: SPINRAZA royalties and WAINUA royalties

We earn commercial revenue primarily in the form of royalty payments on net sales of SPINRAZA. In 2024, we began earning royalties from WAINUA sales.

Commercial Revenue: TEGSEDI and WAYLIVRA revenue, net

We earn commercial revenue from TEGSEDI and WAYLIVRA sales under our distribution agreements with Sobi. In addition, we receive royalties from PTC Therapeutics International Limited, or PTC, for TEGSEDI and WAYLIVRA sales.

Commercial Revenue: Licensing and other royalty revenue

We also recognize as commercial revenue sales milestone payments and royalties we earn under our partnerships. For example, we earn royalty revenue on net sales of QALSODY, which is included in Licensing and other royalty revenue.

Research and development revenue under collaboration agreements

We enter into collaboration agreements to license and sell our technology on an exclusive or non-exclusive basis. Our collaboration agreements typically contain multiple elements, or performance obligations, including technology licenses or options to obtain technology licenses, research and development, or R&D, services and manufacturing services.

Upfront payments: When we enter into a collaboration agreement and receive an upfront payment, we typically record the entire upfront payment as deferred revenue if our only performance obligation is for R&D services we will provide in the future. We amortize the upfront payment into revenue as we perform the R&D services. If part or all of the upfront payment is a license fee, we recognize as revenue the portion related to the license when we deliver the license to our partner because our partner has full use of the license and we do not have any additional performance obligations related to the license after delivery.

Milestone payments: We include variable consideration in the transaction price when it is probable. We typically include milestone payments for R&D services in the transaction price when they are achieved. We include these milestone payments when they are achieved because typically there is considerable uncertainty in the R&D processes that trigger these payments. Similarly, we include approval milestone payments in the transaction price once the medicine is approved by the applicable regulatory agency. We will recognize sales-based milestone payments in the period in which we achieve the milestone under the sales-based royalty exception allowed under accounting rules.

We recognize milestone payments that relate to an ongoing performance obligation over our period of performance. For example, when we achieve a milestone payment from a partner for advancing a clinical study under a collaboration agreement, we add the milestone payment to the transaction price if the milestone relates to an ongoing R&D services performance obligation and recognize revenue related to the milestone payment over our estimated period of performance. If we have partially completed our performance obligation, then we record a cumulative-effect adjustment in the period we add the milestone payment to the transaction price.

Conversely, we recognize in full those milestone payments that we earn based on our partners’ activities when our partner achieves the milestone event and we do not have a performance obligation.

License fees: We recognize as revenue the total amount we determine to be the relative stand-alone selling price of a license when we deliver the license to our partner because our partner has full use of the license and we do not have any additional performance obligations related to the license after delivery.

WAINUA (Eplontersen) Collaboration with AstraZeneca

In 2021, we entered into a joint development and commercialization agreement with AstraZeneca to develop and commercialize WAINUA for the treatment of transthyretin amyloidosis, or ATTR. We jointly developed and are preparing to commercialize WAINUA with AstraZeneca in the U.S. We initially granted AstraZeneca exclusive rights to commercialize WAINUA outside the U.S., except for certain Latin American countries. In 2023, we expanded those rights to include Latin America. Under the terms of the agreement, we received a $200 million upfront payment in 2021.

We evaluated our WAINUA collaboration under ASC 808 and identified four material components: (i) the license we granted to AstraZeneca in 2021, (ii) the co-development activities that we and AstraZeneca are performing, (iii) the co-commercialization activities that we and AstraZeneca are performing and (iv) the co-medical affairs activities that we and AstraZeneca are performing.

We determined that we had a vendor-customer relationship within the scope of Accounting Standards Codification, or ASC, Topic 606, Revenue from Contracts with Customers, or ASC 606, for the license we granted to AstraZeneca and as a result we had one performance obligation. For our sole performance obligation, we determined the transaction price was the $200 million upfront payment we received. We recognized the upfront payment in full in 2021 because we did not have any remaining performance obligations after we delivered the license to AstraZeneca.

We also concluded that the co-development activities, the co-commercialization activities and the co-medical affairs activities are within the scope of ASC Topic 808, Collaborative Arrangements, or ASC 808, because we and AstraZeneca are active participants exposed to the risks and benefits of the activities under the collaboration and therefore do not have a vendor-customer relationship. AstraZeneca is currently responsible for 55 percent of the costs associated with the ongoing global Phase 3 development program. Because we are leading the Phase 3 development program, we made an accounting policy election to recognize as non-customer revenue the cost-share funding from AstraZeneca, net of our share of AstraZeneca’s development expenses, in the same period we incur the related development expenses. As AstraZeneca is responsible for the majority of the commercial and medical affairs costs in the U.S. and all costs associated with bringing WAINUA to market outside the U.S., we made an accounting policy election to recognize cost-share funding we receive from AstraZeneca related to commercial and medical affairs activities as reductions of our selling, general and administrative, or SG&A, expense and R&D expense, respectively.

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Paragraph 9
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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-Subparagraph (a)
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Section 50
-Paragraph 12
-Subparagraph (b)
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Section 50
-Paragraph 12
-Subparagraph (d)
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Section 50
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-Subparagraph (e)
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
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-Paragraph 13
-Subparagraph (b)(2)
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

Stock-based Compensation Expense [Abstract]

Stock-based Compensation Expense

3 Months Ended

Mar. 31, 2024

Stock-based Compensation Expense

9. Stock-based Compensation Expense

The following table summarizes stock-based compensation expense for the three months ended March 31, 2024 and 2023 (in thousands):

	Three Months Ended March 31,
	2024		2023
Cost of sales	$	204	$	119
Research, development and patent expense		22,225		19,567
Selling, general and administrative expense		8,911		7,262
Total	$	31,340	$	26,948

As of March 31, 2024, total unrecognized estimated stock-based compensation expense related to non-vested stock options, RSUs and PRSUs was $71.1 million, $112.8 million and $16.8 million, respectively. Our actual expenses may differ from these estimates because we will adjust our unrecognized stock-based compensation expense for future forfeitures, including any PRSUs that do not vest. We expect to recognize the cost of stock-based compensation expense related to our non-vested stock options, RSUs and PRSUs over a weighted average amortization period of 1.4 years, 1.8 years and 2.2 years, respectively.

Refer to Part IV, Item 15, Note 1, Organization and Significant Accounting Policies, of our audited financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2023 for further details on how we determine the fair value of stock options granted, RSUs, PRSUs and stock purchase rights under the ESPP.

For the three months ended March 31, 2024 and 2023, we used the following weighted-average assumptions in our Black-Scholes calculations:

Employee Stock Options:

	Three Months Ended March 31,
	2024			2023
Risk-free interest rate		4.0	%		3.6	%
Dividend yield		0.0	%		0.0	%
Volatility		44.0	%		47.5	%
Expected life	6.3 years			6.3 years

ESPP:

	Three Months Ended March 31,
	2024			2023
Risk-free interest rate		5.3	%		5.2	%
Dividend yield		0.0	%		0.0	%
Volatility		38.4	%		36.7	%
Expected life	6 months			6 months

RSUs:

The weighted-average grant date fair value of RSUs granted to employees for the three months ended March 31, 2024 and 2023 was $53.54 and $39.85 per share, respectively.

PRSUs:

Under the terms of the PRSUs we granted in 2024 and 2023, 100 percent of the PRSUs may vest at the end of the three-year performance period based on our relative TSR as compared to a peer group of companies and as measured at the end of the performance period. Under the terms of the grants, no number of PRSUs is guaranteed to vest and the actual number of PRSUs that will vest at the end of each performance period may be anywhere from zero to 200 percent of the target number depending on our relative TSR.

The weighted-average grant date fair value of PRSUs granted to our executive officers for the three months ended March 31, 2024 and 2023 was $78.41 and $58.99 per share, respectively.

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Income Taxes [Abstract]
Income tax expense	$ 75	$ 11,380

Collaborative Arrangements and Licensing Agreements [Abstract]

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Royalty Revenue Monetization [Abstract]
Proceeds from sale of future royalties in January 2023		$ 0	$ 500,000
Issuance costs related to sale of future royalties		0	(10,434)
Royalty payments to Royalty Pharma		(6,623)	0
Interest expense related to sale of future royalties		17,806	$ 15,363
Net liability related to sale of future royalties		525,072		$ 513,736
Royalty Purchase Agreement [Member]
Royalty Revenue Monetization [Abstract]
Upfront payment received	$ 500,000
Maximum amount of payments receivable for additional milestones		$ 625,000
Effective interest rate		13.50%
Proceeds from sale of future royalties in January 2023	$ 500,000
Issuance costs related to sale of future royalties				(10,434)
Royalty payments to Royalty Pharma		$ (6,623)		(44,628)
Interest expense related to sale of future royalties		17,806		68,238
Amortization of issuance costs related to sale of future royalties		153		560
Net liability related to sale of future royalties		525,072		$ 513,736
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%

Collaborative Arrangements and Licensing Agreements (Tables)

3 Months Ended

Mar. 31, 2024

AstraZeneca [Member]

Revenue from Collaborative Relationship

During the three months ended March 31, 2024 and 2023, we earned the following revenue from our relationship with AstraZeneca (in thousands, except percentage amounts):

	Three Months Ended March 31,
	2024			2023
Revenue from our relationship with AstraZeneca	$	11,685		$	24,425
Percentage of total revenue		10	%		19	%

Biogen [Member]

Collaborative Arrangements and Licensing Agreements [Abstract]

Revenue from Collaborative Relationship

During the three months ended March 31, 2024 and 2023, we earned the following revenue from our relationship with Biogen (in thousands, except percentage amounts):

	Three Months Ended March 31,
	2024			2023
Revenue from our relationship with Biogen	$	59,236		$	70,501
Percentage of total revenue		50	%		54	%

Insider Trading Arrangements

3 Months Ended

Mar. 31, 2024

Material Terms of Trading Arrangement

During the quarter ended March 31, 2024, our Section 16 officers and directors adopted or terminated contracts, instructions or written plans for the purchase or sale of our securities as noted in the table below.

*	Contract, instruction or written plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act.

**	“Non-Rule 10b5-1 trading arrangement” as defined in item 408(c) of Regulation S-K under the Exchange Act.

Action

Date

Trading Arrangement

Total Shares to Be Sold

Expiration Date

Rule 10b5-1*

Non-Rule 10b5-1**

B. Lynne Parshall

Board Member

Termination

January 3, 2024

122,638

Upon the execution of all instructions provided in the plan

Joseph Klein, III

Board Member

Adoption

January 3, 2024

82,000

The earlier to occur of (i) December 31, 2025, and (ii) Upon the execution of all instructions provided in the plan

Joseph Baroldi

EVP, Chief Business Officer

Adoption

January 5, 2024

40,000

The earlier to occur of (i) March 31, 2025, and (ii) Upon the execution of all instructions provided in the plan

Eugene Schneider

EVP, Chief Clinical Development and Operations Officer

Adoption

January 12, 2024

40,633

The earlier to occur of (i) July 29, 2025, and (ii) Upon the execution of all instructions provided in the plan

Elizabeth Hougen

EVP, Finance & Chief Financial Officer

Adoption

January 12, 2024

178,200

The earlier to occur of (i) October 11, 2025, and (ii) Upon the execution of all instructions provided in the plan

Patrick O'Neil

Chief Legal Officer & General Counsel

Termination

February 14, 2024

170,830

Upon the execution of all instructions provided in the plan

B. Lynne Parshall

Board Member

Adoption

February 21, 2024

145,568

The earlier to occur of (i) June 30, 2025, and (ii) Upon the execution of all instructions provided in the plan

Patrick O'Neil

Chief Legal Officer & General Counsel

Adoption

February 21, 2024

252,747

The earlier to occur of (i) May 31, 2025, and (ii) Upon the execution of all instructions provided in the plan

B. Lynne Parshall [Member]

B. Lynne Parshall

Board Member

true

false

Rule 10b5-1 Arrangement Terminated

February 21, 2024

true

Non-Rule 10b5-1 Arrangement Terminated

false

Termination Date

January 3, 2024

Joseph Klein, III [Member]

Joseph Klein, III

Board Member

true

false

January 3, 2024

729 days

82,000

Joseph Baroldi [Member]

Joseph Baroldi

EVP, Chief Business Officer

true

false

January 5, 2024

452 days

Eugene Schneider [Member]

40,000

Eugene Schneider

EVP, Chief Clinical Development and Operations Officer

true

false

January 12, 2024

565 days

Elizabeth Hougen [Member]

40,633

Elizabeth Hougen

EVP, Finance & Chief Financial Officer

true

false

January 12, 2024

639 days

178,200

Patrick O'Neil [Member]

Patrick O'Neil

Chief Legal Officer & General Counsel

true

false

Rule 10b5-1 Arrangement Terminated

February 21, 2024

true

Non-Rule 10b5-1 Arrangement Terminated

false

Termination Date

February 14, 2024

Termination [Member] | B. Lynne Parshall [Member]

Termination [Member] | Patrick O'Neil [Member]

122,638

Adoption [Member] | B. Lynne Parshall [Member]

170,830

496 days

Adoption [Member] | Patrick O'Neil [Member]

145,568

466 days

252,747

Stock-based Compensation Expense (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 31,340	$ 26,948
Cost of Sales [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	204	119
Research, Development and Patent Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	22,225	19,567
Selling, General and Administrative Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	8,911	$ 7,262
Stock Options [Member]
Unrecognized Compensation Expense [Abstract]
Unrecognized compensation expense related to non-vested stock options	$ 71,100
Weighted average period for recognition	1 year 4 months 24 days
Stock Options [Member] \| Employees [Member]
Weighted-Average Assumptions [Abstract]
Risk-free interest rate	4.00%	3.60%
Dividend yield	0.00%	0.00%
Volatility	44.00%	47.50%
Expected life	6 years 3 months 18 days	6 years 3 months 18 days
ESPP [Member]
Weighted-Average Assumptions [Abstract]
Risk-free interest rate	5.30%	5.20%
Dividend yield	0.00%	0.00%
Volatility	38.40%	36.70%
Expected life	6 months	6 months
RSUs [Member]
Unrecognized Compensation Expense [Abstract]
Unrecognized compensation cost related to non-vested units	$ 112,800
Weighted average period for recognition	1 year 9 months 18 days
RSUs [Member] \| Employees [Member]
RSUs and PRSUs [Abstract]
Weighted-average grant date fair value (in dollars per share)	$ 53.54	$ 39.85
PRSUs [Member]
Unrecognized Compensation Expense [Abstract]
Unrecognized compensation cost related to non-vested units	$ 16,800
Weighted average period for recognition	2 years 2 months 12 days
PRSUs [Member] \| Executive Officers [Member]
RSUs and PRSUs [Abstract]
Weighted-average grant date fair value (in dollars per share)	$ 78.41	$ 58.99
PRSUs [Member] \| Granted in 2024 [Member]
RSUs and PRSUs [Abstract]
Vesting percentage	100.00%
Vesting period	3 years
Number of units guaranteed to vest (in shares)	0
PRSUs [Member] \| Granted in 2024 [Member] \| Minimum [Member]
RSUs and PRSUs [Abstract]
Percentage of units guaranteed to vest	0.00%
PRSUs [Member] \| Granted in 2024 [Member] \| Maximum [Member]
RSUs and PRSUs [Abstract]
Percentage of units guaranteed to vest	200.00%
PRSUs [Member] \| Granted in 2023 [Member] \| Executive Officers [Member]
RSUs and PRSUs [Abstract]
Vesting percentage	100.00%
Vesting period	3 years
Number of units guaranteed to vest (in shares)	0
PRSUs [Member] \| Granted in 2023 [Member] \| Executive Officers [Member] \| Minimum [Member]
RSUs and PRSUs [Abstract]
Percentage of units guaranteed to vest	0.00%
PRSUs [Member] \| Granted in 2023 [Member] \| Executive Officers [Member] \| Maximum [Member]
RSUs and PRSUs [Abstract]
Percentage of units guaranteed to vest	200.00%

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2024
Income Taxes [Abstract]
Income Taxes	10. Income Taxes We recorded income tax expense of $0.1 million for the three months ended March 31, 2024 compared to $11.4 million for the same period in 2023. The decrease in income tax expense relates primarily to the impact of the royalty purchase agreement with Royalty Pharma on income tax expense for the three months ended March 31, 2023. We reflected the Royalty Pharma transaction as a taxable sale, which required us to include the proceeds from the sale, net of currently deductible issuance costs, as taxable income in 2023. We continue to maintain a full valuation allowance on all of our net deferred tax assets.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

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