Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended
	Oct. 31, 2016	Jul. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments in contingent consideration	$ 64,000
Fair value of contingent consideration obligation, short-term	4,551,000	$ 4,534,000
Fair value of contingent consideration obligation, long-term	7,752,000	7,705,000
PocketSonics
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments in contingent consideration	0
Fair value of contingent consideration obligation, short-term	$ 2,000,000	$ 2,000,000
Contingent consideration obligation, payment date	Apr. 30, 2017
Oncura
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments in contingent consideration	$ 100,000
Fair value of contingent consideration obligation, short-term	2,500,000
Fair value of contingent consideration obligation, long-term	$ 7,800,000