Financial Instruments and Fair Value Measurements - (Tables)

3 Months Ended

Mar. 31, 2018

The financial instruments measured at fair value on a recurring basis at March 31, 2018 were as follows:



	Level 1		Level 2		Level 3		Total Fair Value
Cash equivalents:
Money market funds	$	5,690	$	—	$	—	$	5,690
Commercial paper	179,181		—		—		179,181
	184,871		—		—		184,871

Investments - debt securities:
U.S. Treasury securities	9,901		—		—		9,901
Corporate debt securities	—		36,445		—		36,445
	9,901		36,445		—		46,346

Investments - equity securities:
Preferred stock	10,728		34,200		—		44,928

Restricted investments:
Short-term bond	3,227		—		—		3,227
Money market fund	165		—		—		165
	3,392		—		—		3,392
	$	208,892	$	70,645	$	—	$	279,537

The financial instruments measured at fair value on a recurring basis at December 31, 2017 were as follows:



	Level 1		Level 2		Level 3		Total Fair Value
Cash equivalents:
Money market funds	$	10,505	$	—	$	—	$	10,505
Commercial paper	159,970		—		—		159,970
	170,475		—		—		170,475

Investments - debt securities:
U.S. Treasury securities	9,870		—		—		9,870
Corporate debt securities	—		66,375		—		66,375
	9,870		66,375		—		76,245

Investments - equity securities:
Preferred stock	10,717		24,306		—		35,023

Restricted investments:
Short-term bond	4,251		—		—		4,251
Money market fund	218		—		—		218
	4,469		—		—		4,469
	$	195,531	$	90,681	$	—	$	286,212

The carrying amount and fair value, measured on a nonrecurring basis, of the Company’s financial instruments were as follows:



	March 31, 2018					December 31, 2017
	Carrying value		Fair value		Level	Carrying value		Fair value		Level
Assets
Investments held by special purpose entities:
Time deposit	$	200,000	$	200,000	3	$	200,000	$	200,000	3
U.S. Treasury securities and cash equivalents	$	7,618	$	7,303	1	$	7,989	$	7,797	1
Liabilities
Senior notes held by special purpose entity	$	176,595	$	191,373	3	$	176,537	$	198,530	3