Reconciliation of Weighted Average Shares Outstanding for Basic and Diluted Net Income Per Share (Detail) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Earnings Per Share Disclosure [Line Items]
Net income	$ 5,186	$ 1,298	$ 8,437	$ 1,575
Weighted average shares used in computing basic net income per share	34,917	34,106	34,798	34,061
Net income per share - Basic	$ 0.15	$ 0.04	$ 0.24	$ 0.05
Net income	$ 5,186	$ 1,298	$ 8,437	$ 1,575
Weighted average shares used in computing basic net income per share	34,917	34,106	34,798	34,061
Effect of dilutive securities	856	1,072	917	1,129
Weighted average shares used in computing diluted net income per share	35,773	35,178	35,715	35,190
Net income per share - Diluted	$ 0.14	$ 0.04	$ 0.24	$ 0.04