Marketable Securities and Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of Marketable Securities

The following tables present details of the Company’s marketable securities as of September 30, 2017 and December 31, 2016 (in thousands):

	September 30, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Short-term:
Investment securities	$	56,719	$	12	$	(32	)	$	56,699
Long-term:
Investment securities	29,837		22		(50		)	29,809
Total	$	86,556	$	34	$	(82	)	$	86,508

	December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Short-term:
Investment securities	$	63,135	$	7	$	(39	)	$	63,103
Commercial paper	5,641		1		(2		)	5,640
Long-term:
Investment securities	30,985		16		(34		)	30,967
Total	$	99,761	$	24	$	(75	)	$	99,710

Schedule of the Fair Value of the Company's Financial Assets Measured at Fair Value on a Recurring Basis Based on the Three-Tier Value Hierarchy

The following tables set forth the fair value of the Company’s financial assets measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 based on the three-tier value hierarchy (in thousands):

	September 30, 2017
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds and other funds	$	512,929	$	—	$	—	$	512,929
Short-term investments:
Investment securities	—		56,699		—		56,699
Restricted cash:
Certificate of deposit	5,000		—		—		5,000
Long-term:
Investment securities	—		29,809		—		29,809
Total	$	517,929	$	86,508	$	—	$	604,437

	December 31, 2016
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	200,867	$	—	$	—	$	200,867
Short-term investments:
Investment securities	—		63,103		—		63,103
Commercial paper	—		5,640		—		5,640
Restricted cash:
Certificate of deposit	5,000		—		—		5,000
Long-term:
Investment securities	—		30,967		—		30,967
Total	$	205,867	$	99,710	$	—	$	305,577