Allowance Accounts

The following table sets forth the activity in our valuation accounts for each of the three years in the period ended December 31, 2018 (in thousands):



	Allowance for Uncollectible Accounts			Deferred Tax Asset Valuation Allowance

Balance at December 31, 2015	$	350		$	1,936
Additions ⁽¹⁾	1,778			—
Deductions ⁽²⁾	(350		)	—
Adjustments ⁽³⁾	—			1,835
Balance at December 31, 2016	1,778			3,771
Additions ^{(1) (4)}	1,206			2,788
Deductions ⁽²⁾	(232		)	—
Adjustments ⁽³⁾	—			5,778
Balance at December 31, 2017	2,752			12,337
Deductions ⁽²⁾	(2,752		)	—
Adjustments ⁽⁵⁾	—			5,603
Balance at December 31, 2018	$	—		$	17,940


(1)	The increase in allowance for uncollectible accounts primarily reflects charges associated with the provision for uncertain collection of a portion of our existing trade receivables related to our Robotics segment.


(2)	The decrease in allowance for uncollectible accounts reflects the write-offs of trade receivables that are either settled or deemed uncollectible.


(3)	The increase in valuation allowance primarily reflects additional net operating losses in Brazil and in our Robotics segment in the U.K. for which insufficient future taxable income exists to offset the losses.


(4)	The addition of a deferred tax asset valuation allowance reflects management’s view that we will not be able to fully realize our foreign tax credits available from 2015 within the carryforward period.


(5)	The increase in valuation allowance primarily reflects additional net operating losses in our Robotics segment in the U.K. for which insufficient future taxable income exists to offset the losses.

See Note 2 for a detailed discussion regarding our accounting policy on accounts and notes receivable and allowance for uncollectible accounts and Note 7 for a detailed discussion of the valuation allowance related to our deferred tax assets.