Goodwill and intangible assets - Additional Information (Detail) (USD $)	12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2009
Cost of Sales
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 890,000	$ 435,000	$ 435,000
Selling, General and Administrative Expense
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 574,000	$ 525,000	$ 525,000