Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2017	Jul. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments in contingent consideration		$ (8,103,000)
Fair value of contingent consideration obligation, short-term	$ 3,096,000	3,096,000	$ 4,534,000
Fair value of contingent consideration obligation, long-term	1,040,000	1,040,000	7,705,000
PocketSonics
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments in contingent consideration	0	0
Fair value of contingent consideration obligation, short-term	$ 2,000,000	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	$ (8,200,000)	(8,100,000)	$ 100,000
Fair value of contingent consideration obligation, short-term	1,100,000	1,100,000
Fair value of contingent consideration obligation, long-term	$ 1,000,000	$ 1,000,000