Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Cash and cash equivalents consisted of the following (in thousands):

	December 31,
	2018		2017
Cash	$	38,783	$	103,716
US treasury notes and bills		49,934		—
Money market funds		541		569,942
Total cash and cash equivalents	$	89,258	$	673,658

Schedule of Property and Equipment

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

	December 31,
	2018			2017
Leasehold improvements	$	101,200		$	93,758
Building shell (Refer to Note 8)		53,880			53,879
Laboratory equipment		16,405			19,497
Machinery		8,382			—
Computer equipment		6,473			6,006
Furniture and fixtures		5,690			5,575
Construction in progress		367			10,402
Total property and equipment	$	192,397		$	189,117
Less: accumulated depreciation		(65,199	)		(59,641	)
Property and equipment, net	$	127,198		$	129,476

Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Investments

The Company’s investments consist of available-for-sale debt investments, marketable equity investments, term deposit and certificate of deposit. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s investments by major investments type are summarized in the tables below (in thousands):

	December 31, 2018
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
US treasury notes and bills	$	467,296	$	109	$	(69	)	$	467,336
Term deposit		80,000		—		—			80,000
Certificates of deposit		30,000		—		(90	)		29,910
Bond and mutual funds		10,464		20		—			10,484
Equity investments		125		109		—			234
Total investments	$	587,885	$	238	$	(159	)	$	587,964

	December 31, 2017
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
Corporate bonds	$	53,985	$	4	$	(46	)	$	53,943
Bond and mutual funds		17,249		1,153		—			18,402
Equity investments		126		95		—			221
Total investments	$	71,360	$	1,252	$	(46	)	$	72,566

Summary of Contractual Maturities Available-for-Sale Investments and Term Deposit

The contractual maturities of the available-for-sale investments and term deposit were as follows (in thousands):

	December 31, 2018
Within one year	$	532,144
After one year through four years		45,102
Total debt investments		577,246
Bond and mutual funds		10,484
Equity investments		234
Total investments	$	587,964

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	December 31,
	2018		2017
Preclinical and clinical trial accruals	$	35,413	$	32,321
Payroll and related accruals		21,430		18,810
Property taxes and other		1,095		4,201
Professional services		2,648		1,991
Other		5,537		6,458
Total accrued liabilities	$	66,123	$	63,781