Net Loss per Share (Tables)

6 Months Ended

Jun. 30, 2015

Earnings Per Share [Abstract]

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 the three and six months ended June 30, 2015 and 2014:

	Three Months Ended June 30,						Six Months Ended June 30,
	2015			2014			2015			2014
	(in thousands, except share and per share data)
Numerator
Net loss	$	(9,244	)	$	(8,187	)	$	(16,926	)	$	(16,665	)
Accretion of preferred stock to redemption value		(23,788	)		(15,464	)		(35,061	)		(27,642	)
Net loss attributable to common stockholders, basic and diluted	$	(33,032	)	$	(23,651	)	$	(51,987	)	$	(44,307	)
Denominator
Weighted-average common shares outstanding, basic and diluted		12,745,051			12,762,938			12,693,900			12,740,052
Net loss per share attributable to common stockholders, basic and diluted	$	(2.59	)	$	(1.85	)	$	(4.10	)	$	(3.48	)

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:

	Three and Six Months Ended June 30,
	2015		2014
Options to purchase common stock		4,187,854		3,711,137
Unvested restricted stock		398,779		24,877
Warrants to purchase common stock		200,000		200,000
Convertible preferred stock		16,382,615		13,696,099
Total		21,169,248		17,632,113

Schedule of Pro Forma Net Loss Per Share

Pro Forma Net Loss Per Share

	Three Months Ended June 30,			Six Months Ended June 30,
	2015			2015
	(in thousands, except share and per share data)
Numerator
Net loss attributable to common stockholders	$	(33,032	)	$	(51,987	)
Accretion of preferred stock to redemption value		23,788			35,061
Beneficial conversion charge relating to Series D IPO Participation Payment		(14,161	)		(14,161	)
Net loss attributable to common stockholders, basic and diluted	$	(23,405	)	$	(31,087	)
Denominator
Weighted-average common shares outstanding, basic and diluted		12,745,051			12,693,900
Pro forma adjustment to reflect assumed conversion of convertible preferred stock		16,382,615			16,382,615
Pro forma adjustment to reflect common stock issuable in connection with Series D IPO Participation Payment		1,939,990			1,939,990
Pro forma adjustment to reflect common stock issuable upon closing of IPO		7,417,500			7,417,500
Pro forma adjustment to reflect common stock issuable upon closing of the private placement issuance		312,500			312,500
Weighted-average common shares outstanding, basic and diluted		38,797,656			38,746,505
Net loss per share attributable to common stockholders, basic and diluted	$	(0.60	)	$	(0.80	)