Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2020

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

Schedule II - Valuation and Qualifying Accounts

Financial Statement Schedule.

All other schedules have been omitted because the information required to be set forth therein is not applicable or is shown in the financial statements or notes thereto. The table below presents Schedule II, Valuation and Qualifying Accounts, detailing the activity of the allowance for doubtful accounts receivable for the years ended December 31, 2020, 2019 and 2018 (in thousands):

Description	Balance at Beginning of Year		Charged to expenses		Write offs		Balance at End of Year
Allowance for doubtful accounts receivable:
Year ended December 31, 2020	$	45	$	(32)	$	—	$	13
Year ended December 31, 2019	$	22	$	23	$	—	$	45
Year ended December 31, 2018	$	149	$	(123)	$	4	$	22