Net Income (Loss) per Share Attributable to Common Stock:

Net income (loss) per share attributable to common stock is computed by dividing the net income (loss) attributable to common stock by the weighted-average number of common shares outstanding. The Company has outstanding stock options and redeemable convertible preferred stock, which are included in the calculation of diluted net income (loss) attributable to common stock per share whenever doing so would be dilutive.

The Company calculates basic and diluted net income (loss) per share attributable to common stock in conformity with the two-class method required for companies with participating securities. The Company considers all series of redeemable convertible preferred stock to be participating securities. Under the two-class method, net loss attributable to common stock is not allocated to the redeemable convertible preferred stock as the holders of redeemable convertible preferred stock do not have a contractual obligation to share in losses.

Diluted net income (loss) per share attributable to common stock is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, redeemable convertible preferred stock are considered anti-dilutive securities for all periods ended September 30, 2017 and for the three months ended September 30, 2016. For the nine month period ended September 30, 2016 the inclusion of the Company's redeemable convertible preferred stock was dilutive. For the nine month period ended September 30, 2016 the fair value of the redeemable convertible preferred stock declined, resulting in accretion income. The if-converted method of calculating earnings per share resulted in undistributed earnings attributable to participating securities, and conversion of redeemable convertible preferred stock occurring at the beginning of the period. The undistributed earnings attributable to participating securities do not represent a distribution to existing stockholders' paid out of offering proceeds. Options were excluded in the calculation of weighted average shares used to compute diluted income (loss) for all periods presented except the three month period ended September 30, 2016.

The following table sets forth the calculation of basic and diluted net income (loss) per share attributable to common stock during the periods presented:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2016			2017			2016				2017

Numerator:
Net income (loss)	$	5,700		$	10,558		$	(17,191	)		$	(13,203	)
Accretion of redeemable convertible preferred stock	(3,050		)	(40,224		)	56,819				(175,915		)
Undistributed earnings attributable to participating securities	(2,105		)	—			(31,483		)		—
Net income (loss) attributable to common stock—basic	545			(29,666		)	8,145				(189,118		)
Net income (loss) attributable to common stock—diluted	545			(29,666		)	(17,191		)	(1)	(189,118		)

Denominator:
Weighted average shares used to compute net income (loss) per share attributable to common stock—basic	14,441,246			58,868,903			14,339,820				29,678,082
Weighted average shares used to compute net income (loss) per share attributable to common stock—diluted	17,855,205			58,868,903			69,761,822				29,678,082
Net income (loss) per share attributable to common stock—basic	$	0.04		$	(0.50	)	$	0.57			$	(6.37	)
Net income (loss) per share attributable to common stock—diluted	$	0.03		$	(0.50	)	$	(0.25	)		$	(6.37	)

(1) A reconciliation of net income (loss) attributable to common stock—basic to net income (loss) attributable to common stock—diluted is as follows:
Net income (loss) attributable to common stock—basic							$	8,145
Add-back: Accretion due to application of if-converted							(56,819		)
Add-back: Undistributed earnings attributable to participating securities due to application of if-converted							31,483
Net income (loss) attributable to common stock—diluted							$	(17,191	)

The following outstanding shares of common stock equivalents were excluded from the computation of the diluted net income (loss) per share attributable to common stock for the periods presented because their effect would have been anti-dilutive. For the three and nine months ended September 30, 2017 the redeemable convertible preferred stock were anti-dilutive, but converted to common stock on a one-for-one basis on August 2, 2017 upon the successful completion of the IPO, and as such were included in the weighted average shares outstanding for the period they were outstanding as shares of common stock.



	Three Months Ended September 30,		Nine Months Ended September 30,
	2016	2017	2016	2017

Redeemable convertible preferred stock	55,422,002	55,422,002	—	55,422,002
Options outstanding	4,117,639	13,298,339	12,679,454	13,298,339
Total	59,539,641	68,720,341	12,679,454	68,720,341