4. Prepaid Expenses and Other Current Assets (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Prepaid expenses and other current assets	$ 449,840	$ 1,035,379
Collaborative Development Agreement [Member]
Prepaid expenses and other current assets	95,766	191,531
Prepaid Rent [Member]
Prepaid expenses and other current assets	31,773	55,211
Vendor Advances [Member]
Prepaid expenses and other current assets	7,867	43,219
Prepaid Service Agreements [Member]
Prepaid expenses and other current assets	174,920	578,732
Employee Advance and Other Payroll Related Items [Member]
Prepaid expenses and other current assets	16,208	15,734
Other Prepaid Expenses and Current Assets [Member]
Prepaid expenses and other current assets	$ 123,306	$ 150,952