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Common Stock - Additional Information (Detail) - USD ($)
6 Months Ended
Nov. 12, 2015
Jun. 30, 2016
Dec. 31, 2015
Class Of Stock [Line Items]      
Common stock, shares outstanding   38,497,107 38,446,000
Cowen      
Class Of Stock [Line Items]      
Issuance of common stock, (in shares)   0  
Maximum | Cowen      
Class Of Stock [Line Items]      
Common stock sales agreement aggregate sales proceeds $ 90,000,000