Computation of Basic and Diluted Net Income Loss Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Basic Net Income (Loss) Per Share
Net income (loss)	$ 3,119	$ (4,594)
Weighted average shares used in computing basic net income (loss) per share	39,144	38,268
Net income (loss) per share - basic	$ 0.08	$ (0.12)
Diluted Net Income (Loss) Per Share
Net income (loss)	$ 3,119	$ (4,594)
Weighted average shares used in computing basic net income (loss) per share	39,144	38,268
Effect of dilutive securities	2,405
Weighted average shares used in computing diluted net income (loss) per share	41,549	38,268
Net income (loss) per share - diluted	$ 0.08	$ (0.12)