Accounts Receivable (Details Textual) - USD ($)		6 Months Ended		12 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Accounts Receivable [Abstract]
Allowances for doubtful accounts	[1]	$ 785,895		$ 839,895
Provision for doubtful accounts		0		810,580
Collection of doubtful accounts		54,000
Accounts receivable write offs		$ 0		$ 4,920

[1] The allowance for doubtful accounts is primarily due to unpaid billings on a contract that is currently in dispute.