Allowance Accounts (Tables)

12 Months Ended

Dec. 31, 2020

SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]

Summary of activity in valuation accounts

The following table sets forth the activity in our valuation accounts for each of the three years in the period ended December 31, 2020 (in thousands): 

	Allowance for Credit Losses		Deferred Tax Asset Valuation Allowance
Balance at December 31, 2017	$	2,752	$	12,337
Deductions (1)	(2,752)		—
Adjustments (2)	—		5,603
Balance at December 31, 2018	—		17,940
Adjustments (2)	—		691
Balance at December 31, 2019	—		18,631
Additions (3)	2,684		—
Adjustments (2) (4)	785		1,091
Balance at December 31, 2020	$	3,469	$	19,722

(1)The decrease in allowance for credit losses reflects the write-offs of accounts receivable that are either settled or deemed uncollectible

(2)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.

(3)The additions in allowance for credit losses reflect credit loss reserves during 2020.

(4)The adjustment in allowance for credit losses reflects provision for current expected credit losses upon the adoption of ASU No. 2016-13 on January 1, 2020.