Revenue from Contracts with Customers (Tables)

9 Months Ended

Sep. 30, 2020

Revenue From Contract With Customer [Abstract]

Summary of Product and Service Revenue Disaggregated by Geographic Region

The following table summarizes the Company’s product and service revenue disaggregated by geographic region, which is determined based on customer location, for the three and nine months ended September 30, 2020 and 2019:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
United States	$	3,119	$	2,986	$	7,559	$	7,644
South Korea		642		2,018		2,048		5,840
Europe		761		697		2,301		2,422
Asia (excluding South Korea)		1,463		1,181		3,447		2,729
Other		87		73		224		260
Total1	$	6,072	$	6,955	$	15,579	$	18,895

Summary of Information about Receivables and Contract Liabilities from Contracts with Customers

The following table provides information about receivables and contract liabilities from contracts with customers:

	Classification	As of September 30, 2020		As of December 31, 2019
Accounts receivable, current	Accounts receivable, net	$	2,429	$	3,384
Notes receivable, current	Notes receivable, net	$	451	$	502
Notes receivable, long-term	Notes and other receivables, long-term, net	$	538	$	827
Contract liability, current	Deferred revenue	$	836	$	777
Contract liability, non-current	Other long-term liabilities	$	47	$	118

The following table provides information about contract liabilities from contracts with customers:

	Amount
Contract liabilities as of December 31, 2018	$	994
Billings not yet recognized as revenue		619
Beginning contract liabilities recognized as revenue		(687	)
Contract liabilities as of September 30, 2019	$	926
Contract liabilities as of December 31, 2019	$	895
Billings not yet recognized as revenue		658
Beginning contract liabilities recognized as revenue		(670	)
Contract liabilities as of September 30, 2020	$	883

Summary of Allowance for Accounts Receivable

The following table summarizes the activity in the allowance for accounts receivable:

	Amount
Accounts receivable, allowance for doubtful accounts as of    January 1, 2020	$	—
Impact of adoption of ASC 326		15
Provision for doubtful accounts		28
Write-offs		(20	)
Accounts receivable, allowance for doubtful accounts as of    September 30, 2020	$	23

Summary of Allowance for Notes Receivable

The following table summarizes the activity in the allowance for notes receivable:

	Amount
Notes receivable, allowance for doubtful accounts as of    January 1, 2020	$	—
Impact of adoption of ASC 326	19
Provision for doubtful accounts	1
Write-offs		—
Notes receivable, allowance for doubtful accounts as of    September 30, 2020	$	20