Certain Financial Statement Information - Realized Gain on Short-Term Investments and Interest Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Interest Income, Net
Net realized gain on short-term investments	$ 127	$ 5	$ 1,557	$ 0
Interest income, net	130	388	319	729
Realized gain on short-term investments and interest income, net	$ 257	$ 393	$ 1,876	$ 729