Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2018

Accounts Receivable [Abstract]

Summary of accounts receivable

	2018			2017
Billed:
Block sales	$	14,723		$	—
Construction services		1,619,498			2,470,526
Engineering services		400,877			196,008
Retainage receivable		543,417			373,576
Other receivable		7,706			—
Total gross receivables		2,586,221			3,040,110
Less: allowance for doubtful accounts (1)		(839,895	)		(34,235	)
Total net receivables	$	1,746,326		$	3,005,875
(1) The change in allowance for doubtful accounts is primarily due to unpaid billings on a contract that is currently in dispute.