Short-term Investments - Summary of Investments in Continuous Unrealized Loss Position (Detail)	Sep. 30, 2015 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair value	$ 13,275
Less Than 12 Months, Gross unrealized losses	(8)
12 Months or Greater, Fair value	2,000
12 Months or Greater, Gross unrealized losses	(1)
Total, Fair value	15,275
Total, Gross unrealized losses	(9)
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair value	13,275
Less Than 12 Months, Gross unrealized losses	(8)
12 Months or Greater, Fair value	2,000
12 Months or Greater, Gross unrealized losses	(1)
Total, Fair value	15,275
Total, Gross unrealized losses	$ (9)