Balance Sheet Components

12 Months Ended

Dec. 31, 2019

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Inventory and Other Assets

Inventory consisted of the following (in thousands):


	December 31,
	2019		2018
Raw materials	$	1,574	$	676
Finished goods	2,463		1,386
Total	$	4,037	$	2,062

The Company uses Printed Circuit Board Assemblies (“PCBAs”), in each wearable Zio XT and Zio AT monitor as well as the wireless gateway used in conjunction with the Zio AT monitor. The PCBAs are used numerous times and have useful lives beyond one year. Each time a PCBA is used in a wearable Zio XT or Zio AT monitor, or a wireless gateway is used with a Zio AT monitor a portion of the cost of the PCBA and/or gateway is recorded as a cost of revenue. The PCBAs are recorded as other assets and were $7.4 million and $2.5 million as of December 31, 2019, and December 31, 2018, respectively. The amortization was $3.6 million, $3.1 million and $2.1 million for the years ending December 31, 2019, 2018, and 2017, respectively.

Property and Equipment, Net

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


	December 31,
	2019		2018
Laboratory and manufacturing equipment	$	4,238	$	2,750
Computer equipment and software	2,315		1,062
Furniture and fixtures	3,669		925
Leasehold improvements	7,597		726
Internal-use software	16,277		8,925
Total property and equipment, gross	34,096		14,388
Less: accumulated depreciation and amortization	(7,632)		(5,230)
Total property and equipment, net	$	26,464	$	9,158

Depreciation and amortization expense for the years ended December 31, 2019, 2018 and 2017 was $3.4 million, $2.3 million, and $1.6 million, respectively.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):


	December 31,
	2019		2018
Accrued vacation	$	3,809	$	2,825
Accrued payroll and related expenses	19,156		18,188
Accrued ESPP Contributions	417		373
Accrued professional services fees	2,846		1,249
Claims payable	2,802		2,374
Other	3,556		1,679
Total accrued liabilities	$	32,586	$	26,688