Certain Financial Statement Information Interest Income/Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Schedule of Interest Income, Net
Interest income	$ 519	$ 685	$ 1,389	$ 1,915
Net realized gain on short-term investments	6	207	3,290	1,401
Interest income, net	$ 525	$ 892	$ 4,679	$ 3,316