FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2015

Schedule of cash equivalents, restricted cash and marketable securities by security type

Cash equivalents, restricted cash and marketable securities by security type at December 31, 2015 were as follows:

(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Included in cash and cash equivalents:
Money market funds	$	4,577	$	—	$	—		$	4,577
Government-sponsored enterprise securities		1,999		—		—			1,999
Commercial paper		7,599		—		—			7,599
Corporate notes		5,002		—		(1	)		5,001

	$	19,177	$	—	$	(1	)	$	19,176


Restricted cash:
Certificate of deposit	$	267	$	—	$	—		$	267


Marketable securities:
Government-sponsored enterprise securities (due in 1 to 2 years)	$	10,007	$	—	$	(57	)	$	9,950
Commercial paper (due in less than 1 year)		27,661		49		(2	)		27,708
Corporate notes (due in less than 1 year)		64,892		1		(77	)		64,816
Corporate notes (due in 1 to 2 years)		22,837		—		(126	)		22,711

	$	125,397	$	50	$	(262	)	$	125,185

Cash equivalents, restricted cash and marketable securities by security type at December 31, 2014 were as follows:

(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Included in cash and cash equivalents:
Money market funds	$	40,342	$	—	$	—		$	40,342


Restricted cash:
Certificate of deposit	$	266	$	—	$	—		$	266


Marketable securities:
Government-sponsored enterprise securities (due in less than 1 year)	$	401	$	—	$	(1	)	$	400
Government-sponsored enterprise securities (due in 1 to 2 years)		6,556		—		(7	)		6,549
Commercial paper (due in less than 1 year)		10,985		14		—			10,999
Corporate notes (due in less than 1 year)		97,307		2		(63	)		97,246
Corporate notes (due in 1 to 2 years)		12,412		—		(29	)		12,383

	$	127,661	$	16	$	(100	)	$	127,577

Schedule of cash equivalents and marketable securities with unrealized losses

	Less Than 12 Months					12 Months or Greater					Total
(In thousands)	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
As of December 31, 2015:
Government-sponsored enterprise securities (due in 1 to 2 years)	$	9,950	$	(57	)	$	—	$	—		$	9,950	$	(57	)
Commercial paper (due in less than 1 year)		7,834		(2	)		—		—			7,834		(2	)
Corporate notes (due in less than 1 year)		61,006		(71	)		6,301		(7	)		67,307		(78	)
Corporate notes (due in 1 to 2 years)		22,711		(126	)		—		—			22,711		(126	)

	$	101,501	$	(256	)	$	6,301	$	(7	)	$	107,802	$	(263	)


As of December 31, 2014:
Government-sponsored enterprise securities (due in less than 1 year)	$	400	$	(1	)	$	—	$	—		$	400	$	(1	)
Government-sponsored enterprise securities (due in 1 to 2 years)		5,549		(7	)		—		—			5,549		(7	)
Corporate notes (due in less than 1 year)		92,989		(63	)		—		—			92,989		(63	)
Corporate notes (due in 1 to 2 years)		12,383		(29	)		—		—			12,383		(29	)

	$	111,321	$	(100	)	$	—	$	—		$	111,321	$	(100	)

Schedule of financial instruments measured at fair value on recurring basis

The following table presents information about our financial instruments that are measured at fair value on a recurring basis as of December 31, 2015 and indicates the fair value category assigned.

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
Assets
Money market funds(1)	$	4,577	$	—	$	—	$	4,577
Government-sponsored enterprise securities(1)(3)		—		11,949		—		11,949
Commercial paper(1)(2)		—		35,307		—		35,307
Corporate notes(1)(2)(3)		—		92,528		—		92,528

Total	$	4,577	$	139,784	$	—	$	144,361

The following table presents information about our financial instruments that are measured at fair value on a recurring basis as of December 31, 2014 and indicates the fair value category assigned.

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in Active Markets for Identical Assets / Liabilities		Significant Other Observable Inputs		Significant Unobservable Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
Assets
Money market funds(1)	$	40,342	$	—	$	—	$	40,342
Government-sponsored enterprise securities(2)(3)		—		6,949		—		6,949
Commercial paper(2)		—		10,999		—		10,999
Corporate notes(2)(3)		—		109,629		—		109,629

Total	$	40,342	$	127,577	$	—	$	167,919


Liabilities
Derivatives(4)	$	—	$	—	$	16	$	16


(1)	Included in cash and cash equivalents on our balance sheets.
(2)	Included in current portion of marketable securities on our balance sheets.
(3)	Included in noncurrent portion of marketable securities on our balance sheets.
(4)	Included in fair value of derivatives on our balance sheets.

Schedule of rollforward of the balance sheet amounts for financial instruments in Level 3 category

	Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Year Ended December 31, 2015
(In thousands)	Fair Value at December 31, 2014		Total Unrealized Gain Included in Earnings(1)			Purchases, Sales, Issuances, Settlements		Transfers In and/or Out of Level 3		Fair Value at December 31, 2015		Change in Unrealized Gain Related to Financial Instruments Held at December 31, 2015
Derivative liabilities	$	16	$	(16	)	$	—	$	—	$	—	$	—


(1)	Reported as unrealized gain on derivatives on our statements of operations.