Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities - Schedule of Marketable Securities (Detail)

v3.10.0.1
Marketable Securities - Schedule of Marketable Securities (Detail) - Corporate Debt [Member] - USD ($)
Sep. 30, 2018
Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]    
Marketable Securities, Amortized Cost $ 26,664,512 $ 39,933,684
Marketable Securities, Unrealized Gains 54  
Marketable Securities, Unrealized Losses (19,429) (74,820)
Marketable Securities, Fair Value $ 26,645,137 $ 39,858,864