Earnings per Share

12 Months Ended

Dec. 31, 2021

Basic EPS excludes dilution and is computed by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock using the treasury stock method. Potentially dilutive securities (consisting primarily of the Convertible Notes calculated using the if-converted and treasury stock method and warrants, stock options and RSUs calculated using the treasury stock method) are excluded from the diluted EPS computation in loss periods and when the applicable exercise price is greater than the market price on the period end date as their effect would be anti-dilutive.

The calculation of basic and diluted earnings per share was as follows (in thousands, except share and per share data):


	Year Ended December 31,
	2021		2020		2019
Net loss attributable to common stockholders	$	(52,368)	$	(114,119)	$	(40,486)
Weighted-average common shares outstanding	103,246,308		96,111,547		78,322,496
Basic and diluted net loss per share	$	(0.51)	$	(1.19)	$	(0.52)

For the year ended December 31, 2021, the computation of diluted EPS excluded 26,318,509 shares, primarily related to convertible notes, warrants, stock options, RSUs and ESPP for which the effect would have been anti-dilutive.

The following is a summary of outstanding anti-dilutive potential common stock that was excluded from diluted net loss per share attributable to stockholders in the following periods:


	Year Ended December 31,
(in thousands)	2021	2020	2019
Convertible notes	14,341	14,784	22,314
Warrants	2,500	2,500	2,838
Non-qualified stock options	8,086	8,480	9,027
Restricted stock units	1,248	417	414
Employee Stock Purchase Plan	144	25	98
Rights agreement	—	—	198