Fourth Quarter Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2022

Fourth Quarter Financial Data (Unaudited) [Abstract]

Fourth Quarter Financial Data (Unaudited)

10. Fourth Quarter Financial Data (Unaudited)

The following financial information reflects all normal recurring adjustments, which are, in the opinion of management, necessary for a fair statement of the results of the interim periods. Summarized fourth quarter data for 2022 and 2021 are as follows (in thousands, except per share data).

Three Months Ended December 31,	2022			2021
Revenue (1)	$	151,890		$	440,006
Operating expenses (2)	$	359,909		$	219,403
Income (loss) from operations	$	(208,019	)	$	220,603
Net income (loss) (3)	$	(52,430	)	$	224,613
Basic net income (loss) per share (4) (5)	$	(0.37	)	$	1.59
Diluted net income (loss) per share (4) (6)	$	(0.37	)	$	1.41

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(1) Revenue was lower in the three months ended December 31, 2022 compared to the same period in 2021 due to the $200 million we earned in the fourth quarter of 2021 from AstraZeneca to jointly develop and commercialize eplontersen.

(2) Operating expenses were higher in the three months ended December 31, 2022 compared to the same period in 2021 primarily due to the $80 million upfront payment we made for our collaboration with Metagenomi in the fourth quarter of 2022.

(3) Our net loss for the three months ended December 31, 2022 includes the $150.1 million gain we recognized from the sale and leaseback transaction for our headquarters in Carlsbad, California.

(4) We compute net income (loss) per share independently for each quarter during the year.

(5) 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) by our weighted-average number of common shares outstanding during the period.

(6) We had net income for the fourth quarter of 2021. 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 the period as follows (in thousands except per share amounts):

Three Months Ended December 31, 2021	Income (Numerator)		Shares (Denominator)		Per-Share Amount
Net income available to Ionis common stockholders	$	224,612		141,205	$	1.59
Effect of dilutive securities:
Shares issuable upon exercise of stock options		—		46
Shares issuable upon restricted stock award issuance		—		1,065
Shares issuable related to our ESPP		—		34
Shares issuable related to our 0 percent convertible notes		777		10,936
Shares issuable related to our 0.125 percent convertible notes		716		6,590
Shares issuable related to our 1 percent convertible notes		105		464
Income available to Ionis common stockholders, plus assumed conversions	$	226,210		160,340	$	1.41