Cash, Cash Equivalents and Restricted Cash - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jan. 31, 2018	Jul. 31, 2017	Jan. 31, 2017	Jul. 31, 2016
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 21,966	$ 20,708	$ 30,587
Restricted cash			1,000
Total cash, cash equivalents and restricted cash	$ 21,966	$ 20,708	$ 31,587	$ 13,428