Valuation and Qualifying Accounts Allowance for Returns and Doubtful Accounts (Tables)

12 Months Ended

Dec. 31, 2017

Valuation and Qualifying Accounts [Abstract]

Schedule of Valuation Accounts

Period Ended	Balance at Beginning of Period		Charges / (Benefits) to Revenue	(Increases) Deductions	Balance at End of Period
December 31, 2017	$	260,676	141,234	47,368	$	354,542
December 31, 2016	$	191,285	104,228	34,837	$	260,676