Business Combination - Additional Information (Detail) (USD $)	0 Months Ended	6 Months Ended	0 Months Ended	1 Months Ended		3 Months Ended	6 Months Ended
	Dec. 01, 2013	Jan. 31, 2015	Nov. 26, 2014	Jan. 31, 2014 Facility	Feb. 28, 2014	Jan. 31, 2014	Jan. 31, 2014	Jul. 31, 2014
Business Acquisition [Line Items]
Aggregated purchase price	$ 106,009,000
Repayment of the promissory notes principal amount		16,250,000
Promissory notes								18,000,000
Gain on repayment of subordinated debt		1,750,000
Fair value of identifiable intangible assets		12,000,000
Estimated weighted average useful life of acquired intangible assets		3 years 9 months 18 days
Indefinite lived trademarks		6,700,000
Purchase Agreement
Business Acquisition [Line Items]
Aggregated purchase price	93,500,000	106,000,000
Cash payment for the acquisition	73,500,000
Original principal amount of promissory notes issued	20,000,000			20,000,000		20,000,000	20,000,000
Increase in purchase price	12,500,000
Number of facilities				2
Principal amount of promissory notes reduced		1,750,000		2,000,000	2,000,000	2,000,000	2,000,000
Repayment of the promissory notes principal amount			16,250,000
Promissory notes			18,000,000
Gain on repayment of subordinated debt			1,750,000
Purchase Agreement | London Interbank Offered Rate (LIBOR)
Business Acquisition [Line Items]
Promissory notes interest rate spread on London Interbank Offered rate					10.00%
ECT and Multitest
Business Acquisition [Line Items]
Aggregated purchase price		106,009,000
Cash payment for the acquisition		88,009,000
Estimated weighted average useful life of acquired intangible assets		6 years 10 months 24 days
Indefinite lived trademarks		6,700,000
Business acquisition charges	$ 400,000					$ 2,200,000	$ 2,200,000