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Summary of Significant Accounting Policies - Additional Information (Detail) - shares
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Property, Plant and Equipment [Line Items]    
Short-term investment maturity period Three months or less  
Weighted average number of common shares outstanding 7,541,111 7,209,653
Minimum [Member]    
Property, Plant and Equipment [Line Items]    
Property and Equipment, estimated useful life 3 years  
Maximum [Member]    
Property, Plant and Equipment [Line Items]    
Property and Equipment, estimated useful life 30 years