Financial Instruments and Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2019

Financial Instruments and Fair Value Measurements

Schedule of Financial Instruments Measured at Fair Value on Recurring Basis

	June 30, 2019
							Total Fair
	Level 1		Level 2		Level 3		Value
Cash equivalents:
Money market funds	$	1,816	$	—	$	—	$	1,816
Commercial paper		154,241		—		—		154,241
U.S. Treasury securities		6,982		—		—		6,982
		163,039		—		—		163,039
Investments - debt securities:
Corporate debt securities		—		2,832		—		2,832
		—		2,832		—		2,832
Investments - equity securities:
Preferred stock		10,792		25,478		—		36,270
Restricted investments:
Short-term bond		2,221		—		—		2,221
Money market fund		113		—		—		113
		2,334		—		—		2,334
	$	176,165	$	28,310	$	—	$	204,475

	December 31, 2018
							Total Fair
	Level 1		Level 2		Level 3		Value
Cash equivalents:
Money market funds	$	43,346	$	—	$	—	$	43,346
Commercial paper		107,586		—		—		107,586
U.S. Treasury securities		29,998		—		—		29,998
		180,930		—		—		180,930
Investments - debt securities:
U.S. Treasury securities		6,937		—		—		6,937
Corporate debt securities		—		2,021		—		2,021
		6,937		2,021		—		8,958
Investments - equity securities:
Preferred stock		10,470		25,662		—		36,132
Restricted investments:
Short-term bond		3,265		—		—		3,265
Money market fund		167		—		—		167
		3,432		—		—		3,432
	$	201,769	$	27,683	$	—	$	229,452

Schedule of Carrying Amount and Fair Value Measured on Nonrecurring Basis of Financial Instruments

	June 30, 2019					December 31, 2018
	Carrying					Carrying
	value		Fair value		Level	value		Fair value		Level
Assets
Investments held by SPEs:
Time deposit	$	200,000	$	200,000	3	$	200,000	$	200,000	3
U.S. Treasury securities and cash	$	7,055	$	6,997	1	$	7,384	$	7,092	1
Liabilities
Senior Notes held by SPE	$	176,899	$	204,080	3	$	176,775	$	193,293	3