Marketable Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Weighted-average remaining maturity period of marketable debt securities, months	12 months
Minimum
Schedule of Available-for-sale Securities [Line Items]
Remaining maturities of marketable debt securities	2017-04
Maximum
Schedule of Available-for-sale Securities [Line Items]
Remaining maturities of marketable debt securities	2019-08