Net Loss per Share Attributable to Common Stockholders

12 Months Ended

Dec. 31, 2017

Net Loss per Share Attributable to Common Stockholders [Abstract]

Net Loss per Share Attributable to Common Stockholders

5. Net Loss per Share Attributable to Common Stockholders

Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock outstanding for the period. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company  (in thousands, except share and per share amounts):

	Years Ended
	December 31,
	2017		2016		2015
Numerator – basic and diluted:
Net loss attributable to common stockholders	$	(81,692)	$	(230,488)	$	(147,082)
Denominator – basic and diluted:
Weighted average common stock outstanding used to compute basic and diluted net loss per share		57,405,331		23,674,512		8,127,781
Net loss per share, basic and diluted	$	(1.42)	$	(9.74)	$	(18.10)

The amounts in the table below were excluded from the calculation of diluted net loss per share, due to their anti-dilutive effect:

	Years Ended
	December 31,
	2017		2016		2015
Convertible preferred stock		3,351,717		3,191,843		3,191,843
Options to purchase common stock		8,496,872		6,437,515		1,685,248
Warrants to purchase common stock		14,699,990		1,328,452		1,328,452
Total shares of common stock equivalents		26,548,579		10,957,810		6,205,543