SUMMARY OF CRITICAL ACCOUNTING POLICIES AND ESTIMATES - Summary of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 17,754,312	$ 4,099,655	$ 498,219
Restricted cash	100,125	100,170	100,007
Cash and cash equivalents and restricted cash as shown in the consolidated statements of cash flows	$ 17,854,437	$ 4,199,825	$ 598,226	$ 2,849,831