Marketable Securities - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Marketable securities purchased	$ 8,677	$ 2,714
Marketable securities matured and sold	$ 2,900	$ 3,350
Weighted average maturity	7 months 3 days
Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable securities maturity period	38 days
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable securities maturity period	11 months