Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basic Net Income Per Share
Net income	$ 8,875	$ 7,735	$ 21,785	$ 16,594
Weighted average shares used in computing basic net income per share	43,129	42,228	42,971	41,963
Net income per share - basic	$ 0.21	$ 0.18	$ 0.51	$ 0.40
Diluted Net Income Per Share
Net income	$ 8,875	$ 7,735	$ 21,785	$ 16,594
Weighted average shares used in computing basic net income per share	43,129	42,228	42,971	41,963
Effect of dilutive securities	1,451	2,694	1,522	2,815
Weighted average shares used in computing diluted net income per share	44,580	44,922	44,493	44,778
Net income per share - diluted	$ 0.20	$ 0.17	$ 0.49	$ 0.37