Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Assets:
Total assets at fair value	$ 24,517,796	$ 25,927,662
Money Market Funds [Member]
Assets:
Total assets at fair value	70,212	35,886
U.S. Reverse Repurchase Agreements [Member]
Assets:
Total assets at fair value	11,550,000	12,950,000
US Government Agencies Securities [Member]
Assets:
Total assets at fair value	12,897,584	12,941,776
Level 1 [Member]
Assets:
Total assets at fair value	70,212	35,886
Level 1 [Member] | Money Market Funds [Member]
Assets:
Total assets at fair value	70,212	35,886
Level 2 [Member]
Assets:
Total assets at fair value	24,447,584	25,891,776
Level 2 [Member] | U.S. Reverse Repurchase Agreements [Member]
Assets:
Total assets at fair value	11,550,000	12,950,000
Level 2 [Member] | US Government Agencies Securities [Member]
Assets:
Total assets at fair value	$ 12,897,584	$ 12,941,776