Net Income (Loss) Per Share Attributable to Common Shareholders

12 Months Ended

Dec. 31, 2019

Net Income (Loss) Per Share Attributable to Common Shareholders

10. Net Income (Loss) Per Share Attributable to Common Shareholders

Basic net loss per share is calculated by dividing net loss attributable to common shareholders by the weighted-average number of common shares outstanding during the period. Diluted net income per share is calculated by dividing the net income attributable to common shareholders by the weighted-average number of common share equivalents outstanding for the period, including any dilutive effect from outstanding stock options and warrants using the treasury stock method.

The following table sets forth the computation of basic and diluted net income (loss) per share for the periods ended (in thousands, except per share amounts):

	Year ended December 31,
	2019		2018			2017
Basic net income (loss) per common share calculation:
Net income (loss) attributable to common shareholders	$	66,858	$	(164,981	)	$	(68,357	)
Net income (loss) attributable to common shareholders - basic	$	66,858	$	(164,981	)	$	(68,357	)

Basic weighted-average common shares outstanding		54,392,304		47,964,368			40,057,365
Basic net income (loss) per common share	$	1.23	$	(3.44	)	$	(1.71	)

Diluted net income (loss) per common share calculation:
Net income (loss) attributable to common shareholders	$	66,858	$	(164,981	)	$	(68,357	)
Net income (loss) attributable to common shareholders - diluted	$	66,858	$	(164,981	)	$	(68,357	)

Weighted-average shares used to compute basic net income (loss) per common share		54,392,304		47,964,368			40,057,365
Effect of potentially dilutive securities:
Outstanding options		2,406,962		—			—
Unvested restricted common shares		133,532		—			—
Weighted-average shares used to compute diluted net income (loss) per common share		56,932,798		47,964,368			40,057,365
Diluted net income (loss) per common share	$	1.17	$	(3.44	)	$	(1.71	)

The Company did not include the securities in the following table in the computation of the net income (loss) per share calculations because the effect would have been anti-dilutive during each period:

	Year ended December 31,
	2019		2018		2017
Outstanding options		3,789,129		6,689,311		6,262,339
Unvested restricted common shares		108,625		327,342		157,515
Total		3,897,754		7,016,653		6,419,854