Certain Financial Statement Information Net Realized Gain/Loss on Short-Term Investments and Interest Income/Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Schedule of Interest Income, Net
Net realized gain (loss) on short-term investments	$ 1,430	$ (5)
Interest income, net	189	341
Net realized gain (loss) on short-term investments and interest income	$ 1,619	$ 336