Fair Value Measurements - Additional Information (Detail) - USD ($)			3 Months Ended	6 Months Ended
	Jan. 08, 2016	Sep. 20, 2013	Jan. 31, 2016	Jan. 31, 2016	Jan. 31, 2015	Apr. 30, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated decreases in contingent consideration					$ (62,000)
Oncura
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated decreases in contingent consideration	$ 11,300,000		$ 11,300,000	$ 11,300,000
Amount merger consideration paid	8,400,000
Contingent consideration	$ 11,300,000
PocketSonics
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated decreases 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