Certain Financial Statement Information - Schedule of Realized gain on short-term investments and interest income, net (Details) - USD ($) $ in Thousands	3 Months Ended											12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	[1]	Dec. 31, 2014	Sep. 30, 2014	[2]	Jun. 30, 2014	[3]	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Schedule of Interest Income, Net
Gross realized gain on short-term investments												$ 1,763	$ 1,418	$ 3,474
Gross realized loss on short-term investments												(204)	(65)	(114)
Net realized gain on short-term investments												1,559	1,353	3,360
Interest income, net												679	1,411	1,692
Realized gain on short-term investments and interest income, net	$ 229	$ 169	$ 265	$ 1,644	$ 1,030		$ 475	$ (2,112)		$ 315		$ 2,238	$ 2,764	$ 5,052

[1] The consolidated operating results for the fourth quarter of fiscal 2015 included a charge of $2.1 million related to the Veloce consideration, a charge of $4.1 million related to restructuring and an impairment charge of $0.5 million related to a strategic investment.

[2] The consolidated operating results for the second quarter of fiscal 2015 included an impairment charge of $2.5 million related to a strategic investment.

[3] The consolidated operating results for the first quarter of fiscal 2015 included a charge of $7.1 million related to the Veloce consideration and a charge of $1.2 million related to restructuring.