Net Loss per Share of Common Stock (Tables)

6 Months Ended

Jun. 30, 2013

Net Loss per Share of Common Stock

Schedule of basic and diluted net loss per share

	Three Months Ended June 30,						Six Months Ended June 30,
	2012			2013			2012			2013
	(unaudited)						(unaudited)
Numerator:
Numerator for basic and diluted net loss per share	$	(4,780	)	$	(273	)	$	(13,907	)	$	(5,432	)
Denominator:
Weighted average common shares outstanding for basic and diluted net loss per share	7,389,173			7,760,494			7,460,025			7,744,943
Basic and diluted net loss per share	$	(0.65	)	$	(0.04	)	$	(1.86	)	$	(0.70	)

Schedule of securities excluded from the calculation of weighted average common shares outstanding

	Three Months Ended June 30,		Six Months Ended June 30,
	2012	2013	2012	2013
	(unaudited)		(unaudited)
Preferred stock	32,563,192	32,563,192	32,563,192	32,563,192
Stock option awards	6,781,136	7,111,705	6,781,136	7,111,705
Restricted stock unit awards	—	50,000	—	50,000
Warrants to purchase preferred stock	140,933	140,933	140,933	140,933
	39,485,261	39,865,830	39,485,261	39,865,830

Schedule of computation of pro forma net loss per share

	Three Months Ended June 30, 2013			Six Months Ended June 30, 2013
Numerator (in thousands):
Historical net loss	$	(273	)	$	(5,432	)
Plus: mark-to-market income(1)	136			136
Plus: Series F Preferred Stock deemed dividend	(15,849		)	(15,849		)
Pro forma numerator for basic and diluted net loss per share attributable to common stockholders	$	(15,986	)	$	(21,145	)
Denominator:
Historical denominator for basic and diluted net loss per share attributable to common stockholders -weighted average shares	7,760,494			7,744,943
Plus: conversion of preferred stock to common stock	34,172,316			34,172,316
Plus: newly issued IPO shares	7,500,000			7,500,000
Pro forma denominator for basic and diluted net loss per share attributable to common stockholders	49,432,810			49,417,259
Pro forma basic and diluted net loss per share attributable to common stockholders	$	(0.32	)	$	(0.43	)

(1) This pro forma expense relates to the outstanding warrants to purchase preferred stock, which were adjusted to fair value through July 2, 2013 (refer to note 2).