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

12 Months Ended

Dec. 31, 2018

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, 2018	$	354,542	(23,080	)	169,350	$	162,112
December 31, 2017	$	260,676	141,234		47,368	$	354,542