Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

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

	March 31, 2018		December 31, 2017
Cash	$	69,559	$	103,716
Money market funds		589,448		569,942
Total cash and cash equivalents	$	659,007	$	673,658

Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments

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

	March 31, 2018
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
Corporate bonds	$	36,529	$	—	$	(92	)	$	36,437
Bond and mutual funds		17,293		1,338		—			18,631
Equity investments		125		74		—			199
Total investments	$	53,947	$	1,412	$	(92	)	$	55,267

	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

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	March 31, 2018		December 31, 2017
Preclinical and clinical trial accruals	$	37,717	$	32,321
Payroll and related accruals		11,919		18,810
Property taxes and other		3,150		4,201
Professional services		2,520		1,991
Other		7,553		6,458
Total accrued liabilities	$	62,859	$	63,781