Short-term Investments - Summary of Investments in Continuous Unrealized Loss Position (Detail) $ in Thousands	Dec. 31, 2015 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair value	$ 24,457
Less Than 12 Months, Gross unrealized losses	(25)
12 Months or Greater, Fair value	2,730
12 Months or Greater, Gross unrealized losses	(4)
Total, Fair value	27,188
Total, Gross unrealized losses	(29)
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair value	23,357
Less Than 12 Months, Gross unrealized losses	(24)
12 Months or Greater, Fair value	2,730
12 Months or Greater, Gross unrealized losses	(4)
Total, Fair value	26,087
Total, Gross unrealized losses	(28)
U.S. government-related debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair value	1,100
Less Than 12 Months, Gross unrealized losses	(1)
12 Months or Greater, Fair value	0
12 Months or Greater, Gross unrealized losses	0
Total, Fair value	1,101
Total, Gross unrealized losses	$ (1)