Earnings Per Share - Summary of Anti-dilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential shares of common stock excluded from the computation of diluted earnings per share	1,376	990	193
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential shares of common stock excluded from the computation of diluted earnings per share	63	138	0
RSUs & PSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential shares of common stock excluded from the computation of diluted earnings per share	1,110	692	183
ESPP purchase rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential shares of common stock excluded from the computation of diluted earnings per share	203	160	10