Accounts Receivable, Net and Revenue Concentrations

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Accounts Receivable, Net and Revenue Concentrations

Accounts Receivable, Net and Revenue Concentrations

Accounts receivable, net were as follows:

	December 31,
(In thousands)	2017			2016
Trade receivables, gross	$	142,299		$	120,965
Allowance for doubtful accounts	(1,064		)	(904		)
Allowance for sales returns	(562		)	(539		)
Net trade receivables	140,673			119,522
Other	10,905			5,070
Accounts receivable, net	$	151,578		$	124,592

Allowance for Doubtful Accounts

Changes in the allowance for doubtful accounts were as follows:

(In thousands)	Year Ended December 31,
	2017			2016			2015
Balance at beginning of period	$	904		$	822		$	616
Additions to costs and expenses	166			183			299
(Write-offs)/Foreign exchange effects	(6		)	(101		)	(93		)
Balance at end of period	$	1,064		$	904		$	822

Sales Returns

The allowance for sales returns at December 31, 2017 and 2016 included reserves for items returned prior to year-end that were not completely processed, and therefore had not yet been removed from the allowance for sales returns balance. If these returns had been fully processed, the allowance for sales returns balance would have been approximately $0.4 million and $0.4 million on December 31, 2017 and 2016, respectively. The value of these returned goods was included in our inventory balance at December 31, 2017 and 2016.

Significant Customers

Net sales to the following customers totaled more than 10% of our net sales:

	Year Ended December 31,
	2017				2016				2015
	$ (thousands)		% of Net Sales		$ (thousands)		% of Net Sales		$ (thousands)		% of Net Sales
Comcast Corporation	$	159,829	23.0	%	$	149,476	22.9	%	$	129,475	21.5	%
AT&T	77,888		11.2		74,704		11.5		80,820		13.4

Trade receivables associated with these significant customers that totaled more than 10% of our accounts receivable, net were as follows:

	December 31,
	2017						2016
	$ (thousands)			% of Accounts Receivable, Net			$ (thousands)		% of Accounts Receivable, Net
Comcast Corporation	$	25,142		16.6	%		$	23,716	19.0	%
AT&T	—		(1)	—		(1)	14,108		11.3

⁽¹⁾ Trade receivables associated with this customer did not total more than 10% of our accounts receivable, net at December 31, 2017.