Loss Per Share

3 Months Ended

Mar. 31, 2023

Basic loss per share is computed by dividing net loss for the period by the weighted-average number of common shares outstanding during the period. Diluted loss per share reflects the additional dilution from potential issuances of common stock, such as stock issuable pursuant to the exercise of stock options, vesting of RSUs and PSUs or purchases under the ESPP. The treasury stock method is used to calculate the potential dilutive effect of these common stock equivalents. Contingently issuable PSU awards are included in the computation of diluted loss per share when the applicable performance criteria would be met and the common shares would be issuable if the end of the reporting period were the end of the contingency period. However, potentially dilutive shares are excluded from the computation of diluted loss per share when their effect is antidilutive.

Because we reported a net loss for all periods presented, all potentially dilutive securities are antidilutive and are excluded from the computation of diluted loss per share for such periods.

The table below provides the weighted-average number of potential common shares associated with outstanding securities not included in our calculation of diluted loss per share for the three months ended March 31, 2023 and 2022 because to do so would be antidilutive or, in the case of PSUs, the applicable performance conditions have not yet been met (in thousands):


	Three Months Ended March 31,
	2023	2022
Stock options	3,389	3,541
RSUs and PSUs	3,420	1,140
ESPP	279	91
Total	7,088	4,772

In addition, in connection with the acquisition of AltheaDx, Inc. (“AltheaDx”), we may be required to issue shares of our common stock to satisfy the contingent consideration obligations, pending the outcome of certain commercial and regulatory milestones, as required by the definitive agreement to acquire AltheaDx. For purposes of calculating diluted loss per share, no such shares were assumed to have been issued because none of the applicable conditions have been met to date. See Note 10 for additional information.