Organization and Summary of Significant Accounting Policies - Weighted Average Number of Shares Outstanding and Income Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator for basic and diluted earnings per share:
Net income	$ 5,086	$ 7,558	$ 3,883	$ 3,391	$ 5,375	$ 5,114	$ 4,457	$ 3,298	$ 19,918	$ 18,244	$ 14,738
Denominator:
Weighted average shares outstanding—basic									52,948	51,880	53,827
Dilutive effect of stock-based awards (in shares)									1,552	2,272	896
Diluted weighted average shares outstanding									54,500	54,152	54,723
Anti-dilutive stock-based awards excluded									177	507	3,205
Net income (loss) per common share:
Basic (in dollars per share)	$ 0.10	$ 0.14	$ 0.07	$ 0.06	$ 0.10	$ 0.10	$ 0.09	$ 0.06	$ 0.38	$ 0.35	$ 0.27
Diluted (in dollars per share)	$ 0.09	$ 0.14	$ 0.07	$ 0.06	$ 0.10	$ 0.10	$ 0.08	$ 0.06	$ 0.37	$ 0.34	$ 0.27