Inventories, Net and Significant Suppliers

Inventories, net were as follows:



	December 31,
(In thousands)	2017			2016
Raw materials	$	43,638		$	33,059
Components	16,214			15,046
Work in process	1,847			5,860
Finished goods	105,178			80,119
Reserve for excess and obsolete inventory	(4,288		)	(4,205		)
Inventories, net	$	162,589		$	129,879

Reserve for Excess and Obsolete Inventory

Changes in the reserve for excess and obsolete inventory were as follows:



	Year Ended December 31,
(In thousands)	2017			2016			2015
Balance at beginning of period	$	4,205		$	3,045		$	2,539
Additions charged to costs and expenses ⁽¹⁾	3,685			3,464			3,070
Sell through⁽²⁾	(1,242		)	(1,116		)	(1,108		)
(Write-offs)/Foreign exchange effects	(2,360		)	(1,188		)	(1,456		)
Balance at end of period	$	4,288		$	4,205		$	3,045


⁽¹⁾	The additions charged to costs and expenses do not include inventory directly written-off that was scrapped during production totaling $0.4 million, $0.3 million, and $0.3 million for the years ended December 31, 2017, 2016, and 2015, respectively. These amounts are production waste and are not included in management’s reserve for excess and obsolete inventory.


⁽²⁾	These amounts represent the reversal of reserves associated with inventory items that were sold during the period.

Significant Suppliers

We purchase integrated circuits, components and finished goods from multiple sources. Purchases from the following supplier totaled more than 10% of our total inventory purchases:



	Year Ended December 31,
	2017				2016				2015 ⁽¹⁾
	$ (thousands)		% of Total Inventory Purchases		$ (thousands)		% of Total Inventory Purchases		$ (thousands)		% of Total Inventory Purchases
Texas Instruments	$	42,058	10.0	%	$	42,370	11.7	%	$	—	—	%

⁽¹⁾ No single supplier provided more than 10% of our total inventory purchases during the year ended December 31, 2015.

Related Party Supplier

We purchase certain printed circuit board assemblies from a related party supplier. The supplier is considered a related party for financial reporting purposes because our Senior Vice President of Strategic Operations owns 40% of this supplier. Inventory purchases from this supplier were as follows:



	Year Ended December 31,
	2017				2016				2015
	$ (thousands)		% of Total Inventory Purchases		$ (thousands)		% of Total Inventory Purchases		$ (thousands)		% of Total Inventory Purchases
Related party supplier	$	5,217	1.2	%	$	6,350	1.8	%	$	8,550	2.5	%

Total accounts payable to this supplier were as follows:



	December 31,
	2017				2016
	$ (thousands)		% of Accounts Payable		$ (thousands)		% of Accounts Payable
Related party supplier	$	1,500	1.3	%	$	1,690	1.7	%

Our payable terms and pricing with this supplier are consistent with the terms offered by other suppliers in the ordinary course of business. The accounting policies that we apply to our transactions with our related party supplier are consistent with those applied in transactions with independent third parties. Corporate management routinely monitors purchases from our related party supplier to ensure these purchases remain consistent with our business objectives.