Certain Financial Statement Information Short-Term Investments Gross Unrealized Losses (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Mar. 31, 2015
Schedule of Gross Unrealized Losses
Less Than 12 Months of Unrealized Losses, Estimated Fair Value	$ 5,688	$ 15,470
Less than 12 Months of Unrealized Losses, Gross Unrealized Losses	(71)	(23)
12 Months or More of Unrealized Losses, Estimated Fair Value	421	475
12 Months or More of Unrealized Losses, Gross Unrealized Losses	(52)	(42)
Total, Estimated Fair Value	6,109	15,945
Total Gross Unrealized Losses	(123)	(65)
Corporate bonds
Schedule of Gross Unrealized Losses
Less Than 12 Months of Unrealized Losses, Estimated Fair Value	3,502	878
Less than 12 Months of Unrealized Losses, Gross Unrealized Losses	(13)	(6)
12 Months or More of Unrealized Losses, Estimated Fair Value	0	0
12 Months or More of Unrealized Losses, Gross Unrealized Losses	0	0
Total, Estimated Fair Value	3,502	878
Total Gross Unrealized Losses	(13)	(6)
Mutual Funds
Schedule of Gross Unrealized Losses
Less Than 12 Months of Unrealized Losses, Estimated Fair Value	2,186	14,592
Less than 12 Months of Unrealized Losses, Gross Unrealized Losses	(58)	(17)
12 Months or More of Unrealized Losses, Estimated Fair Value	421	475
12 Months or More of Unrealized Losses, Gross Unrealized Losses	(52)	(42)
Total, Estimated Fair Value	2,607	15,067
Total Gross Unrealized Losses	$ (110)	$ (59)