Available-for-Sale Securities and Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2016

Available-for-Sale Securities and Fair Value Measurements

Schedule of available-for-sale securities

(In thousands)	March 31, 2016		December 31, 2015
Cash and cash equivalents	$	148,316	$	148,673
Short-term marketable securities	16,414		28,103
Total	$	164,730	$	176,776

Schedule of amortized cost and estimated fair values for available-for-sale securities

	March 31, 2016
(In thousands)	Amortized Cost		Gross Unrealized Losses			Estimated Fair Value
U.S. government agencies	$	6,532	$	(1	)	$	6,531
U.S. corporate notes	1,632		—			1,632
U.S. commercial paper	69,557		—			69,557
Money market funds	87,010		—			87,010
Total	$	164,731	$	(1	)	$	164,730

	December 31, 2015
(In thousands)	Amortized Cost		Gross Unrealized Losses			Estimated Fair Value
U.S. government agencies	$	14,406	$	(1	)	$	14,405
U.S. corporate notes	2,702		(1		)	2,701
U.S. commercial paper	10,997		—			10,997
Money market funds	148,673		—			148,673
Total	$	176,778	$	(2	)	$	176,776

Schedule of estimated fair values

	Estimated Fair Value Measurements as of March 31, 2016 Using:
Types of Instruments	Quoted Price in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
Assets
U.S. government agencies	$	—	$	6,531	$	—	$	6,531
U.S. corporate notes	—		1,632		—		1,632
U.S. commercial paper	—		69,557		—		69,557
Money market funds	87,010		—		—		87,010
Total assets measured at estimated fair value	$	87,010	$	77,720	$	—	$	164,730
Liabilities
Convertible subordinated notes due 2023	$	—	$	199,304	$	—	$	199,304
Non-recourse notes due 2029	—		471,622		—		471,622
Total fair value of liabilities	$	—	$	670,926	$	—	$	670,926

	Estimated Fair Value Measurements as of December 31, 2015 Using:
Types of Instruments	Quoted Price in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
Assets
U.S. government agencies	$	—	$	14,405	$	—	$	14,405
U.S. corporate notes	—		2,701		—		2,701
U.S. commercial paper	—		10,997		—		10,997
Money market funds	148,673		—		—		148,673
Total assets measured at estimated fair value	$	148,673	$	28,103	$	—	$	176,776
Liabilities
Convertible subordinated notes due 2023	$	—	$	189,100	$	—	$	189,100
Non-recourse notes due 2029	—		470,970		—		470,970
Total fair value of liabilities	$	—	$	660,070	$	—	$	660,070