Summary of Significant Accounting Policies - Schedule of Available-for-Sale Securities, All of Which Have Maturities of Twelve Months or Less (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 57,287
Unrealized Gains	1
Unrealized Losses	(9)
Fair Value	57,279
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,796
Unrealized Gains	1
Unrealized Losses	(1)
Fair Value	26,796
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,491
Unrealized Gains
Unrealized Losses	(8)
Fair Value	$ 30,483