Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities - Summary of Marketable Securities (Detail)

v3.8.0.1
Marketable Securities - Summary of Marketable Securities (Detail) - USD ($)
Sep. 30, 2017
Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 70,846,528 $ 18,937,860
Unrealized Gains 1,235 901
Unrealized Losses (24,328) (7,046)
Estimated Fair Value 70,823,435 18,931,715
Corporate debt securities 1 or less years of maturity [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 70,846,528 18,937,860
Unrealized Gains 1,235 901
Unrealized Losses (24,328) (7,046)
Estimated Fair Value $ 70,823,435 $ 18,931,715