Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2022

Stockholders' Equity [Abstract]

Stock Option Activity

The following table summarizes the stock option activity under our stock plans for the year ended December 31, 2022 (in thousands, except per share and contractual life data):

	Number of Shares			Weighted Average Exercise Price Per Share		Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding at December 31, 2021		14,089		$	54.04
Granted		2,864		$	34.78
Exercised		(123	)	$	29.35
Cancelled/forfeited/expired		(1,860	)	$	53.96
Outstanding at December 31, 2022		14,970		$	50.57		4.01	$	12,243
Exercisable at December 31, 2022		10,285		$	53.74		2.56	$	1,651

Restricted Stock Unit Activity

The following table summarizes the RSU activity for the year ended December 31, 2022 (in thousands, except per share data):

	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Non-vested at December 31, 2021		2,618		$	58.05
Granted		1,401		$	36.14
Vested		(958	)	$	57.05
Cancelled/forfeited		(295	)	$	48.61
Non-vested at December 31, 2022		2,766		$	48.30

Performance Restricted Stock Unit Activity

The following table summarizes the PRSU activity for the year ended December 31, 2022 (in thousands, except per share data):

	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Non-vested at December 31, 2021		59		$	79.20
Granted		105		$	42.28
Vested		(16	)	$	75.03
Cancelled/forfeited		(5	)	$	79.11
Non-vested at December 31, 2022		143		$	52.59

Stock-Based Compensation Expense

The following table summarizes stock-based compensation expense for the years ended December 31, 2022, 2021 and 2020 (in thousands):

	Year Ended December 31,
	2022		2021		2020
Cost of sales	$	533	$	456	$	1,991
Research, development and patent		73,704		87,522		115,584
Selling, general and administrative		26,027		32,700		112,542
Total	$	100,264	$	120,678	$	230,117

Weighted-Average Assumptions for Stock Options

Ionis Employee Stock Options:

	Year Ended December 31,
	2022			2021			2020
Risk-free interest rate		2.1	%		0.6	%		1.5	%
Dividend yield		0.0	%		0.0	%		0.0	%
Volatility		54.5	%		54.0	%		58.6	%
Expected life	6.3 years			4.9 years			4.7 years

Ionis Board of Director Stock Options:

	Year Ended December 31,
	2022			2021			2020
Risk-free interest rate		2.9	%		1.2	%		0.5	%
Dividend yield		0.0	%		0.0	%		0.0	%
Volatility		56.2	%		55.9	%		57.6	%
Expected life	7.4 years			7.3 years			6.7 years

Weighted-Average Assumptions for ESPP

Ionis ESPP:

	Year Ended December 31,
	2022			2021			2020
Risk-free interest rate		1.2	%		0.1	%		0.8	%
Dividend yield		0.0	%		0.0	%		0.0	%
Volatility		50.1	%		42.4	%		47.9	%
Expected life	6 months			6 months			6 months