Certain Financial Statement Information - Schedule of Accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	$ 123,105	$ 149,236	$ 81,504
Other than comprehensive loss, net of tax	(2,067)	(1,343)	(5,406)
Balance, end of period	115,038	123,105	149,236
Foreign currency translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(2,067)	(1,678)
Other than comprehensive loss, net of tax	(419)	(389)
Balance, end of period	(2,486)	(2,067)	(1,678)
Unrealized loss on short-term investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(5,419)	(4,465)
Other than comprehensive loss, net of tax	(1,648)	(954)
Balance, end of period	(7,067)	(5,419)	(4,465)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(7,486)	(6,143)	(737)
Other than comprehensive loss, net of tax	(2,067)	(1,343)
Balance, end of period	$ (9,553)	$ (7,486)	$ (6,143)