FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2017

FAIR VALUE MEASUREMENTS

Schedule of fair value measurements along with the level within the fair value hierarchy in which the fair value measurements fall

The following table presents the Company’s fair value measurements as of September 30, 2017 along with the level within the fair value hierarchy in which the fair value measurements in their entirety fall.

			Fair Value Measurement at September 30, 2017 Using:
			Quoted Prices		Significant
			in Active		Other		Significant
			Markets for		Observable		Unobservable
	Fair Value at		Identical Assets		Inputs		Inputs
(In thousands)	September 30, 2017		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents
Cash and money market	$	30,837	$	30,837	$	—	$	—
U.S. government agency securities		20,000		—		20,000		—
Available-for-sale
Marketable securities
Corporate bonds		213,005		—		213,005		—
Asset backed securities		101,113		—		101,113		—
U.S. government agency securities		64,869		—		64,869		—
Commercial paper		20,895		—		20,895		—
Certificates of deposit		11,802		—		11,802		—
Total	$	462,521	$	30,837	$	431,684	$	—

The following table presents the Company’s fair value measurements as of December 31, 2016 along with the level within the fair value hierarchy in which the fair value measurements in their entirety fall.

			Fair Value Measurement at December 31, 2016 Using:
			Quoted Prices		Significant
			in Active		Other		Significant
			Markets for		Observable		Unobservable
	Fair Value at		Identical Assets		Inputs		Inputs
(In thousands)	December 31, 2016		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents
Cash and money market	$	48,921	$	48,921	$	—	$	—
Available-for-sale
Marketable securities
Corporate bonds		136,937		—		136,937		—
Asset backed securities		55,640		—		55,640		—
U.S. government agency securities		49,474		—		49,474		—
Commercial paper		19,076		—		19,076		—
Certificates of deposit		1,052		—		1,052		—
Total	$	311,100	$	48,921	$	262,179	$	—

Schedule of gross unrealized losses and fair values of investments in an unrealized loss position

		September 30, 2017
		Less than 12 months			12 months or greater				Total
(In thousands)		Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
Marketable securities
Corporate bonds	$	131,782	$	(70)	$	14,717	$	(10)	$	146,499	$	(80)
Asset backed securities		93,585		(56)		—		—		93,585		(56)
Commercial paper		5,458		(1)		—		—		5,458		(1)
U.S. government agency securities		64,869		(103)		—		—		64,869		(103)
Total	$	295,694	$	(230)	$	14,717	$	(10)	$	310,411	$	(240)

Summary of contractual maturities available for the sale of investments in debt securities

The following summarizes contractual underlying maturities of the Company’s available-for-sale investments in debt securities at September 30, 2017:

		Due one year or less			Due after one year through four years
(In thousands)		Cost		Fair Value		Cost		Fair Value
Marketable securities
Corporate bonds	$	138,989	$	138,964	$	74,069	$	74,041
U.S. government agency securities		50,016		49,928		14,956		14,941
Commercial paper		20,894		20,895		—		—
Certificates of deposit		9,801		9,802		1,999		2,000
Asset backed securities		17,617		17,612		83,550		83,501
Total	$	237,317	$	237,201	$	174,574	$	174,483