Balance Sheet Components

12 Months Ended

Dec. 31, 2021

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

Balance Sheet Components

Property and Equipment, Net

Property and equipment consisted of the following (in thousands):

	December 31,
	2021		2020
Prototype	$	17,730	$	17,711
Machine and equipment	17,701		17,486
Leasehold improvements	14,088		14,196
Furniture and fixtures	1,295		1,295
Software	1,389		1,389
Construction in progress	1,397		486
Property and equipment, gross	53,600		52,563
Less: accumulated depreciation and amortization	(33,358)		(28,501)
Property and equipment, net	$	20,242	$	24,062

Depreciation and amortization expense related to property and equipment was $6.0 million, $6.4 million and $4.7 million during the years ended December 31, 2021, 2020 and 2019, respectively.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	December 31,
	2021		2020
Accrued payroll and related benefits	$	17,080	$	12,810
Accrued accounts payable	$	3,740	2,810
Payroll withholding tax, sales and other tax payable	$	1,094	1,398
Accrued legal and accounting	$	230	305
Product upgrade reserve	$	2,500	1,500
Other	$	1,911	458
Total accrued liabilities	$	26,555	$	19,281

Deferred Revenue

Deferred revenue consisted of the following (in thousands):

	December 31,
	2021		2020
Deferred revenue:
Product	$	1,322	$	1,888
Services	15,385		8,857
Distribution rights	1,445		1,921
Total deferred revenue	18,152		12,666
Less: current portion of deferred revenue	(13,920)		(10,094)
Noncurrent portion of deferred revenue	$	4,232	$	2,572

Other Long-Term Liabilities

Other long-term liabilities consisted of the following (in thousands):

	December 31,
	2021		2020
Accrued interest, noncurrent portion	$	704	$	99
Asset retirement obligation	962		857
Other accrued costs	981		—
Total other-long term liabilities	$	2,647	$	956