Short-term and Long-term Investments - Summary of Estimated Fair Value of Available-for-Sale Investments Classified by Contractual Maturities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014
Amortized Cost And Fair Value Debt Securities [Abstract]
Due within one year	$ 112,755
After one year through two years	40,212
Aggregate Fair Value	$ 152,967

Amount of debt securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant