Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Summary of Gross Unrealized Gains and Unrealized Losses of Investment Securities Excluding Investments in Money Market Funds

The following is a summary of the gross unrealized gains and unrealized losses on the Company’s investment securities (in thousands):

	December 31, 2018
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Aggregate Fair Value
Investment Securities
Commercial paper	$	119,692	$	—	$	(90	)	$	119,602
Corporate notes		111,652		—		(120	)		111,532
Total securities	$	231,344	$	—	$	(210	)	$	231,134

	December 31, 2017
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Aggregate Fair Value
Investment Securities
Commercial paper	$	61,167	$	—	$	(81	)	$	61,086
Corporate notes		165,712		1		(332	)		165,381
Total securities	$	226,879	$	1	$	(413	)	$	226,467

Summary of Amortized Costs and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities

The amortized costs and estimated fair values of the Company’s available-for-sale securities by contractual maturities as of December 31, 2018 were as follows (in thousands):

	Amortized Cost		Fair Value
Amounts maturing within one year	$	231,344	$	231,134
Amounts after one year through five years		—		—
Total investment securities	$	231,344	$	231,134

Components of Inventories

Inventories (in thousands)

	December 31,
	2018		2017
Raw materials	$	37,453	$	51,602
Finished goods		54,582		46,517
Total inventories	$	92,035	$	98,119

Schedule of Property and Equipment, Net and Depreciation and Amortization Expense

Property and Equipment, Net (in thousands)

	December 31,
	2018			2017
Laboratory equipment	$	2,874		$	2,416
Computer equipment and software		8,751			5,076
Furniture and fixtures		3,903			2,241
Leasehold improvements		4,218			1,221
Construction in process		1,811			2,734
Total		21,557			13,688
Less: Accumulated depreciation and amortization		(8,756	)		(4,869	)
Property and equipment, net	$	12,801		$	8,819

Summary of Accrued Liabilities

Accrued Liabilities (in thousands)

	December 31,
	2018		2017
Accrued payroll and related expenses	$	26,792	$	26,108
Accrued professional fees		1,595		4,734
Accrued taxes		2,506		2,827
Accrued clinical and research expenses		1,105		1,279
Accrued interest		243		243
Accrued warranty		1,236		708
Accrued other		5,313		3,491
Total accrued liabilities	$	38,790	$	39,390