Certain Financial Statement Information - Realized Gain on Short-Term Investments and Interest Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Schedule of Interest Income, Net
Net realized gain (loss) on short-term investments	$ (2)	$ 123	$ 1,557	$ 123
Interest income, net	150	362	467	1,091
Realized gain on short-term investments and interest income, net	$ 148	$ 485	$ 2,024	$ 1,214