AVAILABLE-FOR-SALE SECURITIES AND FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2016

AVAILABLE-FOR-SALE SECURITIES AND FAIR VALUE MEASUREMENTS

Schedule of available-for-sale securities

	December 31,
(In thousands)	2016		2015
Cash and cash equivalents	$	116,396	$	148,673
Short-term marketable securities		32,417		28,103
Total	$	148,813	$	176,776

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

	December 31, 2016
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. government agencies	$	12,428	$	1	$	—	$	12,429
U.S. commercial paper		72,065		—		—		72,065
Money market funds		64,319		—		—		64,319
Total	$	148,812	$	1	$	—	$	148,813

	December 31, 2015
(In thousands)	Amortized Cost		Gross Unrealized Gains		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 December 31, 2016 Using:
	Quoted Price in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
Types of Instruments (In thousands)	Level 1		Level 2		Level 3		Total
Assets
U.S. government agencies	$	—	$	12,429	$	—	$	12,429
U.S. commercial paper		—		72,065		—		72,065
Money market funds		64,319		—		—		64,319
Total assets measured at estimated fair value	$	64,319	$	84,494	$	—	$	148,813
Liabilities
Convertible subordinated notes due 2023	$	—	$	202,125	$	—	$	202,125
Non-recourse notes due 2029		—		487,189		—		487,189
Total fair value of liabilities	$	—	$	689,314	$	—	$	689,314

	Estimated Fair Value Measurements as of December 31, 2015 Using:
	Quoted Price in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
Types of Instruments (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