Revenue from Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 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 years ended December 31, 2020 and 2019:

	Year Ended December 31,
	2020		2019
United States	$	11,604	$	10,918
South Korea		3,077		7,876
Europe		3,588		3,448
Asia (excluding South Korea)		4,193		3,664
Other		319		441
Total1	$	22,781	$	26,347

The table above does not include lease revenue of $3,601 and $4,181 for the years ended December 31, 2020 and 2019, respectively. Refer to Note 6, Leases.

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:

		As of December 31,
	Classification	2020		2019
Accounts receivable, current	Accounts receivable, net	$	2,012	$	3,384
Notes receivable, current	Notes receivable, net	$	444	$	502
Notes receivable, long-term	Notes and other receivables, long-term, net	$	452	$	827
Contract liability, current	Deferred revenue	$	923	$	777
Contract liability, non-current	Other long-term liabilities	$	128	$	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		739
Beginning contract liabilities recognized as revenue		(838	)
Contract liabilities at December 31, 2019		895
Billings not yet recognized as revenue		880
Beginning contract liabilities recognized as revenue		(724	)
Contract liabilities at December 31, 2020	$	1,051

Summary of Allowance for Accounts Receivable

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

	Amount
Accounts receivable, allowance for credit losses as of    January 1, 2020	$	—
Impact of adoption of ASC 326		15
Change in provision for credit losses		24
Write-offs		(20	)
Accounts receivable, allowance for credit losses as of    December 31, 2020	$	19

Summary of Allowance for Notes Receivable

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

	Amount
Notes receivable, allowance for credit losses as of    January 1, 2020	$	—
Impact of adoption of ASC 326	19
Change in provision for credit losses		(1	)
Write-offs		—
Notes receivable, allowance for credit losses as of    December 31, 2020	$	18

Summary of Maturities of Notes Receivables Net Under Extended Payment Terms

Maturities of notes receivables, net under extended payment terms with a significant financing component as of December 31, 2020 are as follows:

Fiscal Year	Amount
2021	$	483
2022		350
2023		126
2024		—
2025		—
Thereafter		—
Total undiscounted cash flows		959
Present value of notes receivable		914
Difference between undiscounted and discounted    cash flows	$	45

Summary of Costs to Obtain Customer Contracts

The following table provides information about the costs to obtain contracts associated with contracts with customers for the years ended December 31, 2020 and 2019:

	Year Ended December 31,
	2020			2019
Beginning balance	$	190		$	80
Additions		379			452
Amortization		(460	)		(342	)
Ending balance	$	109		$	190