Organization and Summary of Significant Accounting Policies - Weighted Average Number of Shares Outstanding and Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator for basic and diluted earnings per share:
Net income	$ 5,104	$ 1,521	$ 6,103	$ 7,205	$ 5,086	$ 7,558	$ 3,883	$ 3,391	$ 19,933	$ 19,918	$ 18,244
Denominator:
Weighted average shares outstanding—basic									53,548	52,948	51,880
Dilutive effect of stock-based awards (in shares)									1,090	1,552	2,272
Diluted weighted average shares outstanding									54,638	54,500	54,152
Anti-dilutive stock-based awards excluded (in shares)									198	177	507
Net income (loss) per common share:
Basic (in dollars per share)	$ 0.10	$ 0.03	$ 0.11	$ 0.14	$ 0.10	$ 0.14	$ 0.07	$ 0.06	$ 0.37	$ 0.38	$ 0.35
Diluted (in dollars per share)	$ 0.09	$ 0.03	$ 0.11	$ 0.13	$ 0.09	$ 0.14	$ 0.07	$ 0.06	$ 0.36	$ 0.37	$ 0.34