Fair Value Measurements (Tables)

3 Months Ended

Jun. 30, 2013

Fair Value Disclosures [Abstract]

Schedule of Assets Measured at Fair Value on a Recurring Basis

Assets measured at fair value on a recurring basis as of June 30, 2013 and March 31, 2013 are as follows:

	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
	(In thousands)
June 30, 2013
Cash and cash equivalents	$	90,899	$	3,653	$	—	$	94,552
Marketable securities:
U.S. government and agency securities		92,458		—		—		92,458
Corporate debt obligations		—		151,644		—		151,644
Mortgage-backed securities		—		52,931		—		52,931
Municipal bonds		—		39,689		—		39,689
Other debt securities		—		595		—		595
		92,458		244,859		—		337,317
	$	183,357	$	248,512	$	—	$	431,869
March 31, 2013
Cash and cash equivalents	$	95,098	$	434	$	—	$	95,532
Marketable securities:
U.S. government and agency securities		113,359		—		—		113,359
Corporate debt obligations		—		154,859		—		154,859
Mortgage-backed securities		—		51,281		—		51,281
Municipal bonds		—		39,872		—		39,872
Other debt securities		—		603		—		603
		113,359		246,615		—		359,974
	$	208,457	$	247,049	$	—	$	455,506