Fair Value Measurements - Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Assets
Total assets at fair value	$ 1,552,090	$ 1,473,950
Level 1
Assets
Total assets at fair value	1,552,090	1,473,950
Investments in securities
Assets
Total assets at fair value	1,552,090	1,473,950
Investments in securities | Level 1
Assets
Total assets at fair value	$ 1,552,090	$ 1,473,950