Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Schedule of Fair Value of Cash Equivalents and Marketable Securities

The following tables present the fair value of cash equivalents and marketable securities in accordance with the hierarchy discussed in Note 2 (in thousands):

	Quoted		Significant
	prices		other		Significant
	in active		observable		unobservable
	markets		inputs		inputs
	(Level 1)		(Level 2)		(Level 3)		Total
June 30, 2019
Cash equivalents:
Money market mutual funds	$	—	$	55,126	$	—	$	55,126
Total cash equivalents		—		55,126		—		55,126
Marketable securities:
U.S. government and federal agency securities		—		103,213		—		103,213
Certificates of deposit		—		8,815		—		8,815
Corporate bonds		—		250,444		—		250,444
Equity securities		32,076		—		—		32,076
Total marketable securities		32,076		362,472		—		394,548
Total cash equivalents and marketable securities	$	32,076	$	417,598	$	—	$	449,674

	Quoted		Significant
	prices		other		Significant
	in active		observable		unobservable
	markets		inputs		inputs
	(Level 1)		(Level 2)		(Level 3)		Total
December 31, 2018
Cash equivalents:
Money market mutual funds	$	—	$	75,542	$	—	$	75,542
Total cash equivalents		—		75,542		—		75,542
Marketable securities:
U.S. government and federal agency securities		—		103,466		—		103,466
Certificates of deposit		—		8,992		—		8,992
Corporate bonds		—		282,561		—		282,561
Total marketable securities		—		395,019		—		395,019
Total cash equivalents and marketable securities	$	—	$	470,561	$	—	$	470,561