Accrued expenses and other liabilities (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Accrued expenses and other liabilities.
Accrued clinical trial expenses	$ 447,674	$ 1,156,618
Compensation and related benefits	183,498	303,870
Other expenses	571,533	215,979
Accrued expenses	$ 1,202,705	$ 1,676,467