Marketable Securities - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Weighted-average remaining maturity period of marketable debt securities, months	14 months
Minimum
Schedule of Available-for-sale Securities [Line Items]
Remaining maturities of marketable debt securities	2017-03
Maximum
Schedule of Available-for-sale Securities [Line Items]
Remaining maturities of marketable debt securities	2019-08