Summary of Financial Assets Measured at Fair Value on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Jun. 30, 2012
Fair Value
Assets:
Fair value measurement disclosure	$ 39,672	$ 119,245
Fair Value | U.S. Treasury bills and money market funds
Assets:
Fair value measurement disclosure	27,023	97,049
Fair Value | Operating cash
Assets:
Fair value measurement disclosure	12,103	18,915
Fair Value | Restricted cash
Assets:
Fair value measurement disclosure	546	3,281
Level 1
Assets:
Fair value measurement disclosure	39,672	119,245
Level 1 | U.S. Treasury bills and money market funds
Assets:
Fair value measurement disclosure	27,023	97,049
Level 1 | Operating cash
Assets:
Fair value measurement disclosure	12,103	18,915
Level 1 | Restricted cash
Assets:
Fair value measurement disclosure	546	3,281
Level 2
Assets:
Fair value measurement disclosure	0	0
Level 2 | U.S. Treasury bills and money market funds
Assets:
Fair value measurement disclosure	0	0
Level 2 | Operating cash
Assets:
Fair value measurement disclosure	0	0
Level 2 | Restricted cash
Assets:
Fair value measurement disclosure	0	0
Level 3
Assets:
Fair value measurement disclosure	0	0
Level 3 | U.S. Treasury bills and money market funds
Assets:
Fair value measurement disclosure	0	0
Level 3 | Operating cash
Assets:
Fair value measurement disclosure	0	0
Level 3 | Restricted cash
Assets:
Fair value measurement disclosure	$ 0	$ 0