Marketable Securities - Summary of Marketable Securities (Detail) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 72,455,706	$ 18,937,860
Unrealized Gains	1,823	901
Unrealized Losses	(24,461)	(7,046)
Estimated Fair Value	72,433,068	18,931,715
Corporate debt securities 1 or less years of maturity [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	72,455,706	18,937,860
Unrealized Gains	1,823	901
Unrealized Losses	(24,461)	(7,046)
Estimated Fair Value	$ 72,433,068	$ 18,931,715