Accounts Receivable, Net and Revenue Concentrations (Tables)

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Schedule of Accounts Receivable and Allowance for Doubtful Accounts

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

Schedule of Significant Customers to Net Sales

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

Schedule of Significant Customers to Accounts Receivable

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.