Summary of Unaudited Quarterly Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net revenue	$ 111,600	$ 122,200	$ 131,500	$ 121,100	$ 138,100	$ 128,000	$ 127,900	$ 114,900	$ 486,372	$ 508,848	$ 540,291
Gross profit	37,800	52,200	57,700	51,600	63,400	54,900	58,800	50,900	$ 199,291	$ 228,065	$ 229,487
Net income (loss)	$ (24,600)	$ (59,700)	$ 7,500	$ 2,500	$ 8,800	$ 5,000	$ (3,000)	$ 1,400
Basic net income (loss) per share	$ (1.98)	$ (4.78)	$ 0.60	$ 0.20	$ 0.71	$ 0.40	$ (0.24)	$ 0.11
Diluted net income (loss) per share	$ (1.98)	$ (4.78)	$ 0.59	$ 0.20	$ 0.70	$ 0.40	$ (0.24)	$ 0.11