3. Allowance for Doubtful Accounts

12 Months Ended

Dec. 31, 2020

Allowance for Credit Loss [Abstract]

3. Allowance for Doubtful Accounts

Changes in the allowance for doubtful accounts are composed of the following:

	Years Ended December 31,
	2020		2019
Balance, beginning of year	$	50	$	50
Provision for doubtful accounts		—		—
Uncollectible accounts written off		—		—
Balance, end of year	$	50	$	50