Net Loss per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2017

Net Loss per Share Attributable to Common Stockholders [Abstract]

Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders

	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)

Anti-dilutive Amounts Excluded From Calculation of Diluted Net Loss per Share

	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