Marketable securities (Tables)

3 Months Ended

Jun. 30, 2013

Marketable securities [Abstract]

Available-for-sale debt securities

Available-for-sale debt securities consist of the following:

	June 30, 2013
(In thousands)	Estimated fair value		Gains in accumulated other comprehensive income		Losses in accumulated other comprehensive income
Current:
Municipal bonds and notes	$	24,244	$	17		–
Government agency bonds		71,584		104	$	(15)
Commercial paper		115,859		–		–
Certificates of deposit		113,939		–		(1)
Corporate bonds		493,522		1,121		(222)
Total current securities		819,148		1,242		(238)
Non-current:
Municipal bonds and notes		10,628		13		(1)
Government agency bonds		171,334		175		(549)
Commercial paper		2,850		–		–
Certificates of deposit		7,999		–		–
Corporate bonds		1,045,360		2,262		(9,510)
Auction rate securities		3,198		–		(752)
Variable rate demand notes		13,650		–		–
Total non-current securities		1,255,019		2,450		(10,812)
Total available-for-sale debt securities	$	2,074,167	$	3,692	$	(11,050)

	March 31, 2013
(In thousands)	Estimated fair value		Gains in accumulated other comprehensive income		Losses in accumulated other comprehensive income
Current:
Municipal bonds and notes	$	34,025	$	34		–
Government agency bonds		87,227		125	$	(10)
Commercial paper		144,293		–		–
Certificates of deposit		47,977		–		(2)
Corporate bonds		425,676		1,286		(33)
Total current securities		739,198		1,445		(45)
Non-current:
Municipal bonds and notes		12,852		37		–
Government agency bonds		186,577		434		(19)
Certificates of deposit		22,999		–		–
Corporate bonds		1,084,194		5,290		(2,150)
Auction rate securities		3,198		–		(752)
Variable rate demand notes		1,500		–		–
Total non-current securities		1,311,320		5,761		(2,921)
Total available-for-sale debt securities	$	2,050,518	$	7,206	$	(2,966)

Contractual maturities of available-for-sale debt securities

Contractual maturities of available-for-sale debt securities at June 30, 2013 are as follows:

(In thousands)

	Estimated fair value
Within one year	$	819,148
After 1-5 years		1,232,394
After 5-10 years		3,500
After 10 years		19,125
	$	2,074,167