FAIR VALUE MEASUREMENTS (Tables)

6 Months Ended

Jun. 30, 2016

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

Cash equivalents, restricted cash and marketable securities by security type at June 30, 2016 were as follows:

			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
(In thousands)	Cost		Gains		Losses			Fair Value
Included in cash and cash equivalents:
Money market funds	$	4,284	$	—	$	—		$	4,284
Corporate notes	1,500		—		—			1,500

	$	5,784	$	—	$	—		$	5,784

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

Marketable securities:
Government-sponsored enterprise securities (due in 1 to 2 years)	$	17,006	$	5	$	—		$	17,011
Commercial paper (due in less than 1 year)	40,000		63		(4		)	40,059
Corporate notes (due in less than 1 year)	62,330		29		(16		)	62,343
Corporate notes (due in 1 to 2 years)	8,499		18		(5		)	8,512

	$	127,835	$	115	$	(25	)	$	127,925

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

			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
(In thousands)	Cost		Gains		Losses			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

Schedule of cash equivalents and marketable securities with unrealized losses

	Less Than 12 Months					12 Months or Greater					Total
			Gross					Gross					Gross
	Estimated		Unrealized			Estimated		Unrealized			Estimated		Unrealized
(In thousands)	Fair Value		Losses			Fair Value		Losses			Fair Value		Losses
As of June 30, 2016:
Commercial paper (due in less than 1 year)	$	6,353	$	(4	)	$	—	$	—		$	6,353	$	(4	)
Corporate notes (due in less than 1 year)	22,879		(9		)	9,130		(7		)	32,009		(16		)
Corporate notes (due in 1 to 2 years)	1,398		(5		)	—		—			1,398		(5		)

	$	30,630	$	(18	)	$	9,130	$	(7	)	$	39,760	$	(25	)

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	)

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 June 30, 2016 and indicates the fair value category assigned.

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in				Significant
	Active Markets for		Significant Other		Unobservable
	Identical Assets		Observable Inputs		Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
Money market funds(1)	$	4,284	$	—	$	—	$	4,284
Government-sponsored enterprise securities(3)	—		17,011		—		17,011
Commercial paper(2)	—		40,059		—		40,059
Corporate notes(1)(2)(3)	—		72,355		—		72,355

Total	$	4,284	$	129,425	$	—	$	133,709

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				Significant
	Active Markets for		Significant Other		Unobservable
	Identical Assets		Observable Inputs		Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
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

(1)

Included in cash and cash equivalents on our condensed balance sheets.

(2)

Included in current portion of marketable securities on our condensed balance sheets.

(3)

Included in noncurrent portion of marketable securities on our condensed balance sheets.