Inventories, Net and Significant Suppliers

Inventories, net were as follows:



	December 31,
(In thousands)	2019			2018
Raw materials	$	61,220		$	68,834
Components	25,239			25,071
Work in process	1,526			5,577
Finished goods	68,175			50,006
Reserve for excess and obsolete inventory	(11,025		)	(5,138		)
Inventories, net	$	145,135		$	144,350

Reserve for Excess and Obsolete Inventory

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



	Year Ended December 31,
(In thousands)	2019			2018			2017
Balance at beginning of period	$	5,138		$	4,288		$	4,205
Additions charged to costs and expenses	12,792			6,702			3,685
Sell through⁽¹⁾	(1,500		)	(1,825		)	(1,242		)
(Write-offs)/Foreign exchange effects	(5,405		)	(4,027		)	(2,360		)
Balance at end of period	$	11,025		$	5,138		$	4,288


⁽¹⁾	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,
	2019				2018				2017
	$ (thousands)		% of Total Inventory Purchases		$ (thousands)		% of Total Inventory Purchases		$ (thousands)		% of Total Inventory Purchases
Texas Instruments	—	⁽¹⁾	—	⁽¹⁾	—	⁽¹⁾	—	⁽¹⁾	$	42,058	10.0	%

⁽¹⁾ Purchases associated with this supplier did not total more than 10% of our total inventory purchases for the indicated period.

Accounts payable from our supplier, Zhejiang Zhen You Electronics Co. Ltd., totaled $11.4 million or 11.1% of our accounts payable balance at December 31, 2019.

Related Party Supplier

During the years ended December 31, 2018 and 2017, we purchased certain printed circuit board assemblies from a related party supplier. The supplier was considered a related party for financial reporting purposes because our Senior Vice President of Strategic Operations owned 40% of this supplier. In the second quarter of 2018, our Senior Vice President sold his interest in this supplier, and thus this supplier is no longer considered a related party.

Total inventory purchases made from this supplier while it was a related party were $1.1 million and $5.2 million during the twelve months ended December 31, 2018, and 2017, respectively.