Leases - Future minimum lease payments (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019	$ 459,331
2020	116,145
Total future minimum lease payments	575,476
Less amount representing interest and taxes	(41,988)
Present value of future minimum lease payments	533,488
Less current maturities	(426,331)	$ (417,524)
Obligations under capital leases - long term	$ 107,157	$ 533,404

Amount of capital lease obligation due within one year or the normal operating cycle, if longer.

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Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal, through the balance sheet date and due to be paid more than one year (or one operating cycle, if longer) after the balance sheet date.

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Amount of minimum lease payments for capital leases.

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Amount of minimum lease payments for capital leases due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount necessary to reduce net minimum lease payments to present value for capital leases.

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Present value of minimum lease payments for capital leases net of executory costs, including amounts paid by the lessee to the lessor for insurance, maintenance and taxes.

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