Fair Value Measurements - Additional Information (Detail) - USD ($)			3 Months Ended	9 Months Ended
	Jan. 08, 2016	Sep. 20, 2013	Apr. 30, 2016	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Increase (decrease) in contingent consideration					$ (62,000)
Oncura
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Increase (decrease) in contingent consideration			$ (1,200,000)
Amount merger consideration paid	$ 8,400,000
Contingent consideration	$ 10,100,000		10,100,000	$ 10,100,000
PocketSonics
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Increase (decrease) in contingent consideration			0	0
Ownership interests						10.00%
Amount merger consideration paid		$ 11,100,000
Contingent consideration		$ 1,900,000	$ 2,000,000	$ 2,000,000