Net Sales by Geographic Area along with Long-Lived Assets by Location (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017	Jul. 31, 2017
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	$ 115,717	$ 103,635	$ 346,279	$ 263,845
Long-lived assets	30,191		30,191		$ 28,509
United States
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	9,921	23,223	33,899	49,928
Long-lived assets	12,923		12,923		14,426
Malaysia
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	8,980	8,318	24,356	21,447
Long-lived assets	4,570		4,570		3,069
Hong Kong / China
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	11,622	14,943	31,594	31,464
Taiwan
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	26,899	13,654	55,417	39,208
Long-lived assets	828		828		375
Thailand
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	6,091	5,251	26,931	17,217
Philippines
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	17,726	14,582	71,837	32,975
Long-lived assets	38		38		82
Germany
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	13,044	6,615	29,544	20,694
Long-lived assets	9,743		9,743		8,579
Singapore
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	7,056	5,197	19,202	17,464
Long-lived assets	305		305		416
China
Segment Reporting Information [Line Items]
Long-lived assets	859		859		285
Japan
Segment Reporting Information [Line Items]
Long-lived assets	630		630		791
All Other Countries
Segment Reporting Information [Line Items]
Sales to unaffiliated customers	14,378	$ 11,852	53,499	$ 33,448
Long-lived assets	$ 295		$ 295		$ 486