Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities - Additional Information (Detail)

v3.7.0.1
Marketable Securities - Additional Information (Detail)
6 Months Ended 12 Months Ended
Jun. 30, 2017
USD ($)
Debt_Security
Jun. 30, 2016
USD ($)
Dec. 31, 2016
USD ($)
Debt_Security
Marketable Securities [Abstract]      
Realized gains or losses on marketable securities $ 0 $ 0  
Maturity period classified current investments Less than one year    
Maturity period classified non-current investments Greater than one year and management does not intend to liquidate within the next twelve months.    
Number of debt securities held | Debt_Security 19   29
Aggregate fair value of debt securities $ 16,829,854   $ 29,343,892