Revenue from Contracts with Customers (Tables)

6 Months Ended

Jun. 30, 2022

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 six months ended June 30, 2022 and 2021:

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
United States	$	4,097	$	3,942	$	8,067	$	7,380
South Korea		662		1,190		2,096		2,188
Europe		956		921		2,575		1,810
Asia (excluding South Korea)		771		633		1,551		1,175
Other		137		96		275		161
Total1	$	6,623	$	6,782	$	14,564	$	12,714

¹ The table above does not include lease revenue of $1,415 and $1,140 for three months ended June 30, 2022 and 2021, respectively, and $2,814 and $2,251 for the six months ended June 30, 2022 and 2021, respectively. Substantially all lease revenue originates from the United States. 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:

	Classification	As of June 30, 2022		As of December 31, 2021
Accounts receivable, current	Accounts receivable, net	$	2,760	$	4,638
Notes receivable, current	Notes receivable, net	$	164	$	350
Notes receivable, long-term	Notes and other receivables, long-term, net	$	29	$	121
Contract liability, current	Deferred revenue	$	937	$	904
Contract liability, non-current	Other long-term liabilities	$	37	$	66

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

	Amount
Contract liabilities as of December 31, 2021	$	970
Billings not yet recognized as revenue		637
Beginning contract liabilities recognized as revenue		(633	)
Contract liabilities as of June 30, 2022	$	974
Contract liabilities as of December 31, 2020	$	1,051
Billings not yet recognized as revenue		713
Beginning contract liabilities recognized as revenue		(622	)
Contract liabilities as of June 30, 2021	$	1,142

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    December 31, 2021	$	47
Provision for credit losses		(6	)
Write-offs		(16	)
Accounts receivable, allowance for credit losses as of    June 30, 2022	$	25
Accounts receivable, allowance for credit losses as of    December 31, 2020	$	19
Provision for credit losses		8
Write-offs		—
Accounts receivable, allowance for credit losses as of    June 30, 2021	$	27

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    December 31, 2021	$	63
Provision for credit losses		130
Write-offs		(11	)
Notes receivable, allowance for credit losses as of    June 30, 2022	$	182
Notes receivable, allowance for credit losses as of    December 31, 2020	$	18
Provision for credit losses		(3	)
Write-offs		—
Notes receivable, allowance for credit losses as of    June 30, 2021	$	15