Net Loss per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Computation of Basic and Diluted Net Loss per Share

The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data):

	Year Ended December 31,
	2016			2015			2014
Numerator
Net loss	$	(13,152	)	$	(22,946	)	$	(16,829	)
Cumulative dividends on redeemable convertible    preferred stock		—			(5,151	)		(2,864	)
Accretion of redeemable convertible preferred stock to    redemption value		—			(98	)		(158	)
Net loss attributable to common stockholders, basic    and diluted	$	(13,152	)	$	(28,195	)	$	(19,851	)
Denominator
Weighted average shares outstanding		28,104,991			7,594,115			3,394,727
Less: weighted average shares subject to repurchase		(629,199	)		(1,301,315	)		(1,637,827	)
Weighted average shares used to compute basic and diluted    net loss per share		27,475,792			6,292,800			1,756,900
Net loss per share attributable to common stockholders:
Basic and diluted	$	(0.48	)	$	(4.48	)	$	(11.30	)

Summary of Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss per Share

The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive:

	As of December 31,
	2016		2015
Common stock subject to repurchase		409,839		990,609
Stock options to purchase common stock		2,141,868		1,318,647