SUMMARY OF CRITICAL ACCOUNTING POLICIES AND ESTIMATES - Summary of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 16,295,062	$ 4,099,655	$ 1,676,808
Restricted cash	100,134	100,170	100,000
Cash and cash equivalents and restricted cash as shown in the consolidated statements of cash flows	$ 16,395,196	$ 4,199,825	$ 1,776,808	$ 2,849,831