Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2016

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis

Financial assets and liabilities measured at fair value on a recurring basis at June 30, 2016 and December 31, 2015, consisted of the following:

(In thousands)	Fair Value Measurements
At June 30, 2016	Total		Level 1		Level 2		Level 3
Money market fund	$	60,754	$	60,754	$	—	$	—
Mutual funds	$	978	$	978	$	—	$	—
Investments
Federal agency notes	$	280,063	$	—	$	280,063	$	—
Commercial paper	$	31,974	$	—	$	31,974	$	—

(In thousands)	Fair Value Measurements
At December 31, 2015	Total		Level 1		Level 2		Level 3
Money market fund	$	54,761	$	54,761	$	—	$	—
Mutual funds	$	743	$	743	$	—	$	—
Investments
Federal agency notes	$	284,757	$	—	$	284,757	$	—
Commercial paper	$	31,672	$	—	$	31,672	$	—

Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis

Assets and liabilities measured at fair value on a nonrecurring basis at June 30, 2016 and December 31, 2015, consisted of the following:

(In thousands)	Fair Value Measurements
At June 30, 2016	Total		Level 1		Level 2		Level 3
1.875% Convertible debentures	$	524	$	—	$	524	$	—
1.75% Convertible debentures	$	307,369	$	—	$	307,369	$	—

(In thousands)	Fair Value Measurements
At December 31, 2015	Total		Level 1		Level 2		Level 3
1.875% Convertible Debentures	$	524	$	—	$	524	$	—
1.75% Convertible Debentures	$	285,446	$	—	$	285,446	$	—
Long-term investments	$	524	$	524	$	—	$	—