Accrued Expenses (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Accrued Expenses (Details)
Accrued expenses, other	$ 190,989	$ 174,489
Accrued interest	541,087	436,581
Accrued warranty costs	91,531	91,531
Accrued Expenses	$ 823,607	$ 702,601