Marketable Securities and Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Schedule of Marketable Securities

The following tables present details of the Company’s marketable securities as of December 31, 2018 and 2017 (in thousands):

	December 31, 2018
	Amortized Cost		Gross Unrealized Losses			Estimated Fair Value
Short-term:
Investment securities	$	114,402	$	(124	)	$	114,278
Long-term:
Investment securities	6,603		(77		)	6,526
Total	$	121,005	$	(201	)	$	120,804

	December 31, 2017
	Amortized Cost		Gross Unrealized Losses			Estimated Fair Value
Short-term:
Investment securities	$	61,129	$	(97	)	$	61,032
Long-term:
Investment securities	21,695		(134		)	21,561
Total	$	82,824	$	(231	)	$	82,593

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 December 31, 2018 and 2017 based on the three-tier value hierarchy described in Note 2, Summary of Significant Accounting Policies (in thousands):

	December 31, 2018
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds and other funds	$	715,086	$	—	$	—	$	715,086
Short-term investments:
Investment securities	—		114,278		—		114,278
Other non-current assets:
Certificate of deposit	5,000		—		—		5,000
Long-term:
Investment securities	—		6,526		—		6,526
Total	$	720,086	$	120,804	$	—	$	840,890

	December 31, 2017
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	488,029	$	—	$	—	$	488,029
Short-term investments:
Investment securities	—		61,032		—		61,032
Other non-current assets
Certificate of deposit	5,000		—		—		5,000
Long-term:
Investment securities	—		21,561		—		21,561
Total	$	493,029	$	82,593	$	—	$	575,622