Quarterly report pursuant to sections 13 or 15(d)

Stockholders' Equity - Additional Information (Detail)

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Stockholders' Equity - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
0 Months Ended 1 Months Ended 9 Months Ended
Nov. 22, 2013
Sep. 30, 2013
Oct. 31, 2013
Sep. 30, 2013
Sep. 30, 2013
Mar. 31, 2014
Dec. 31, 2013
Class of Stock [Line Items]              
Issuance of common stock upon conversion of redeemable convertible preferred stock         2,793,281    
Conversion of preferred stock to common stock         $ 320.0    
Convertible preferred stock issued           0 0
Convertible preferred stock outstanding           0 0
Common stock, shares authorized           100,000,000 100,000,000
Common stock, par value           $ 0.0001 $ 0.0001
Common stock shares sold 604,000 5,366,669 664,300 5,366,669 5,366,669 10,064,495 9,455,064
Warrants to purchase shares of common stock in 2013 financing 120,800 1,073,338 132,860 1,073,338 1,073,338    
Net proceeds from issuance of 2013 financing     2.2 22.8      
Loan facility extinguished in exchange of common stock   624,944   624,944      
Amount of debt cancelled upon issuance of common stock shares   16.9   16.9      
Net proceeds from issuance of 2013 financing $ 2.7 $ 26.8          
Series B-1 Preferred [Member]
             
Class of Stock [Line Items]              
Common stock, shares authorized           100,000,000  
Common stock, par value           $ 0.0001