13. NET LOSS PER SHARE

Net Loss per Share

Basic and diluted net loss per share attributable to common stockholders was calculated as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Numerator:
Net loss	$	(25,281)	$	(12,335)	$	(45,875)	$	(24,774)
Accretion of preferred stock to redemption value		(159,453)		3,323		(199,492)		(8,324)
Net loss attributable to common stockholders	$	(184,734)	$	(9,012)	$	(245,367)	$	(33,098)
Denominator:
Weighted-average number of common shares outstanding—basic and diluted		44,759,435		10,255,078		28,104,372		10,116,021
Net loss per share attributable to common stockholders—basic and diluted	$	(4.13)	$	(0.88)	$	(8.73)	$	(3.27)

The Company’s potentially dilutive securities, which include stock options, redeemable convertible and convertible preferred stock, and warrants to purchase common stock and preferred stock, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted‑average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti‑dilutive effect:


	As of June 30,
	2018	2017
Options to purchase common stock	18,452,393	13,566,354
Unvested restricted stock units	412,521	—
Options to purchase Series E-1 preferred stock (as converted to common stock)	—	837,835
Warrants to purchase common stock	—	106,250
Warrants to purchase redeemable convertible preferred stock (as converted to common stock)	—	167,500
Redeemable convertible preferred stock (as converted to common stock)	—	44,370,560
	18,864,914	59,048,499

The table above excludes shares of common stock issuable upon the conversion of Series A preferred stock and upon the exercise of options to purchase shares of Series A preferred stock as such shares are only convertible into common stock upon the closing of an IPO. The table also excludes shares of common stock issuable upon the exercise of the Company’s liability-classified common stock warrant as the warrant is only exercisable upon the closing of an IPO.