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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator for basic and diluted earnings per share:
Net income	$ 6,341	$ 3,843	$ 3,650	$ 3,463	$ 5,104	$ 1,521	$ 6,103	$ 7,205	$ 17,297	$ 19,933	$ 19,918
Denominator:
Weighted average shares outstanding—basic									52,667	53,548	52,948
Dilutive effect of stock-based awards (in shares)									869	1,090	1,552
Diluted weighted average shares outstanding									53,536	54,638	54,500
Anti-dilutive stock-based awards excluded (in shares)									443	198	177
Net income per common share:
Basic (in dollars per share)	$ 0.12	$ 0.07	$ 0.07	$ 0.06	$ 0.10	$ 0.03	$ 0.11	$ 0.14	$ 0.33	$ 0.37	$ 0.38
Diluted (in dollars per share)	$ 0.12	$ 0.07	$ 0.07	$ 0.06	$ 0.09	$ 0.03	$ 0.11	$ 0.13	$ 0.32	$ 0.36	$ 0.37