Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Basic and Diluted Net Loss Per Share of Common Stock

The following table summarizes the computation of basic and diluted net loss per share of our common stock for 2017, 2016 and 2015:



	Year Ended December 31,
	2017			2016			2015
	(in thousands, except share and per share data)
Numerator:
Net loss	$	(45,470	)	$	(49,000	)	$	(49,857	)
Accretion of preferred stock to redemption value	—			—			(35,061		)
Beneficial conversion charge relating to IPO participation payment	—			—			(14,161		)
Net loss attributable to common stockholders, basic and diluted	$	(45,470	)	$	(49,000	)	$	(99,079	)
Denominator:
Weighted-average common shares outstanding, basic and diluted	42,952,950			41,248,473			24,740,480
Net loss per share attributable to common stockholders, basic and diluted	$	(1.06	)	$	(1.19	)	$	(4.00	)

Anti-Dilutive Securities Excluded from Computation Diluted Weighted Average Shares Outstanding

The following potentially dilutive securities outstanding, prior to the use of the treasury stock method or if-converted method, have been excluded from the computation of diluted weighted-average shares outstanding for the respective periods below because they would have been anti-dilutive:



	Year Ended December 31,
	2017	2016	2015
Options to purchase common stock	4,684,954	4,580,375	4,246,525
Unvested restricted stock	210,083	585,004	1,149,257
Unvested restricted stock units	1,988,509	734,577	—
Warrants to purchase common stock	—	—	100,000
Shares to be issued under ESPP	79,551	91,815	114,271
Total	6,963,097	5,991,771	5,610,053