v2.4.0.8
Net Loss per Share (Details 2) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended 12 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Dec. 31, 2013
Numerator      
Historical net loss attributable to common stockholders $ (7,050) $ (3,746)  
Changes in the fair value of the warrant to purchase Series D redeemable convertible preferred stock (688) 8 33
Net loss attributable to common stockholders (7,137) (3,833)  
Denominator:      
Weighted-average common shares outstanding, basic and diluted (in shares) 7,698,709 7,386,133  
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share) $ (0.93) $ (0.52)  
Pro Forma
      
Numerator      
Historical net loss attributable to common stockholders (7,137)    
Accretion of deferred preferred stock offering costs 87    
Changes in the fair value of the warrant to purchase Series D redeemable convertible preferred stock 688    
Net loss attributable to common stockholders $ (6,362)    
Denominator:      
Weighted-average common shares outstanding, basic and diluted (in shares) 7,698,709    
Plus: conversion of redeemable convertible preferred stock to common stock (in shares) 23,501,208    
Pro forma denominator for basic and diluted net loss per share attributable to common stockholders (in shares) 31,199,917    
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share) $ (0.20)