Revenue from Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 2021

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, 2021 and 2020:

	Year Ended December 31,
	2021		2020
United States	$	15,004	$	11,604
South Korea		4,380		3,077
Europe		5,805		3,588
Asia (excluding South Korea)		3,855		4,193
Other		449		319
Total1	$	29,493	$	22,781

The table above does not include lease revenue of $4,966 and $3,601 for the years ended December 31, 2021 and 2020, respectively. Refer to Note 5, 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	2021		2020
Accounts receivable, current	Accounts receivable, net	$	4,638	$	2,012
Notes receivable, current	Notes receivable, net	$	350	$	444
Notes receivable, long-term	Notes and other receivables, long-term, net	$	121	$	452
Contract liability, current	Deferred revenue	$	904	$	923
Contract liability, non-current	Other long-term liabilities	$	66	$	128

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

	Amount
Contract liabilities as of 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
Billings not yet recognized as revenue		798
Beginning contract liabilities recognized as revenue		(879	)
Contract liabilities at December 31, 2021	$	970

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
Change in provision for credit losses		28
Write-offs		—
Accounts receivable, allowance for credit losses as of    December 31, 2021	$	47

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
Change in provision for credit losses		45
Write-offs		—
Notes receivable, allowance for credit losses as of    December 31, 2021	$	63

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, 2021 are as follows:

Fiscal Year	Amount
2022	$	350
2023		126
2024 and thereafter		—
Total undiscounted cash flows		476
Present value of notes receivable		534
Difference between undiscounted and discounted    cash flows	$	(58	)

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, 2021 and 2020:

	Year Ended December 31,
	2021			2020
Beginning balance	$	109		$	190
Additions		509			379
Amortization		(575	)		(460	)
Ending balance	$	43		$	109